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question:Compare the size of each pair of numbers 3 2.95; 0.08 0.21; 0.6 0.60.
answer:To compare the sizes of the given pairs of numbers, I will analyze each pair individually.1. **Comparing 3 and 2.95:** - The integer part of 3 is greater than the integer part of 2.95. - Therefore, 3 is greater than 2.95.2. **Comparing 0.08 and 0.21:** - Both numbers have the same integer part (0). - The tenth place of 0.08 is 0, while the tenth place of 0.21 is 2. - Since 0 is less than 2, 0.08 is less than 0.21.3. **Comparing 0.6 and 0.60:** - Both numbers have the same integer part (0). - The tenth place of both numbers is 6. - The hundredth place of 0.6 is 0 (since it can be considered as 0.60), and the hundredth place of 0.60 is also 0. - Therefore, 0.6 is equal to 0.60.
question:A certain company had a net profit of 5 million yuan in 2015. Due to reasons such as equipment aging, the company's production capacity is expected to decline year by year. Without technical renovation, it is predicted that the net profit will decrease by 2 million yuan each year starting from 2015. If technical renovation is carried out, a one-time investment of 6 million yuan is required at the beginning of 2016. Excluding the investment for technical renovation, the profit for 2016 is expected to be 7.5 million yuan, and each subsequent year's profit will exceed half of the previous year's profit by 2.5 million yuan.(1) Let the annual net profit of the company without technical renovation be a_n million yuan for the nth year starting from 2016 (with 2016 as the first year), and the annual profit after technical renovation, excluding the renovation investment, be b_n million yuan. Find a_n and b_n.(2) Let the cumulative net profit without technical renovation be A_n million yuan for the nth year starting from 2016 (with 2016 as the first year), and the cumulative profit after technical renovation be B_n million yuan. Find A_n and B_n.(3) Based on the above prediction, how many years must pass from 2016 for the cumulative profit after technical renovation to exceed the cumulative profit without technical renovation?
answer:Okay, so I have this problem about a company's profits with and without technical renovation. It's divided into three parts, and I need to figure out each step by step. Let me start by understanding what each part is asking.**Problem (1):** I need to find expressions for the annual net profit without technical renovation, denoted as ( a_n ), and the annual profit after technical renovation, excluding the investment, denoted as ( b_n ). Alright, starting with ( a_n ). The company had a net profit of 5 million yuan in 2015, and without renovation, the profit decreases by 2 million yuan each year starting from 2015. So, 2016 would be the first year after 2015, which is the starting point for our calculations.So, in 2016 (which is the first year, n=1), the profit would be 5 million minus 2 million, which is 3 million. In 2017 (n=2), it would be 3 million minus 2 million, which is 1 million. Wait, that seems too steep. Let me check the problem again.Wait, it says the net profit will decrease by 2 million yuan each year starting from 2015. So, 2015 is the base year with 5 million. Then 2016 would be 5 - 2 = 3 million, 2017 would be 3 - 2 = 1 million, 2018 would be 1 - 2 = negative, which doesn't make sense. Hmm, maybe I'm misinterpreting.Wait, perhaps the decrease starts from 2015, meaning 2015 is the first year of decrease. So, 2015: 5 million, 2016: 5 - 2 = 3 million, 2017: 3 - 2 = 1 million, and so on. So, yes, it's an arithmetic sequence where each term decreases by 2 million yuan each year.So, the general formula for an arithmetic sequence is ( a_n = a_1 + (n-1)d ), where ( a_1 ) is the first term, ( d ) is the common difference, and ( n ) is the term number. But in this case, since the profit is decreasing, the common difference ( d ) is negative, so ( d = -2 ).But wait, 2016 is the first year, so n=1 corresponds to 2016. So, the first term ( a_1 ) is 3 million yuan (since 2016 is 5 - 2). Therefore, the formula would be:( a_n = 3 + (n - 1)(-2) )Simplifying that:( a_n = 3 - 2(n - 1) )( a_n = 3 - 2n + 2 )( a_n = 5 - 2n )Wait, that can't be right because when n=1, it should be 3, but 5 - 2(1) = 3, which is correct. For n=2, 5 - 4 = 1, which is also correct. For n=3, 5 - 6 = -1, which is negative, but maybe the company can't have negative profit, but the problem doesn't specify, so I guess we just go with the formula.So, ( a_n = 5 - 2n ) million yuan.Now, moving on to ( b_n ), which is the annual profit after technical renovation, excluding the renovation investment. The problem states that in 2016, the profit is expected to be 7.5 million yuan, and each subsequent year's profit will exceed half of the previous year's profit by 2.5 million yuan.Hmm, that sounds a bit more complex. Let me parse that. So, starting from 2016 (n=1), the profit is 7.5 million. For n=2 (2017), the profit is half of 7.5 plus 2.5. Let me compute that:Half of 7.5 is 3.75, plus 2.5 is 6.25 million yuan.For n=3 (2018), it's half of 6.25 plus 2.5. Half of 6.25 is 3.125, plus 2.5 is 5.625 million.Wait, so each year, the profit is half of the previous year's profit plus 2.5 million. That seems like a recursive sequence.So, the general formula for ( b_n ) can be expressed recursively as:( b_1 = 7.5 )( b_n = frac{1}{2}b_{n-1} + 2.5 ) for ( n geq 2 )But the problem asks for an expression for ( b_n ), so I need to find a closed-form formula for this recursive sequence.This is a linear recurrence relation. The general form is ( b_n = a cdot b_{n-1} + c ), where ( a = 1/2 ) and ( c = 2.5 ).The solution to such a recurrence can be found using the method for linear nonhomogeneous recurrence relations. The general solution is the sum of the homogeneous solution and a particular solution.First, solve the homogeneous equation:( b_n - frac{1}{2}b_{n-1} = 0 )The characteristic equation is ( r - frac{1}{2} = 0 ), so ( r = frac{1}{2} ). Therefore, the homogeneous solution is:( b_n^{(h)} = A left( frac{1}{2} right)^n )Now, find a particular solution. Since the nonhomogeneous term is a constant (2.5), we can assume a constant particular solution ( b_n^{(p)} = C ).Substitute into the recurrence:( C - frac{1}{2}C = 2.5 )( frac{1}{2}C = 2.5 )( C = 5 )So, the general solution is:( b_n = A left( frac{1}{2} right)^n + 5 )Now, apply the initial condition ( b_1 = 7.5 ):( 7.5 = A left( frac{1}{2} right)^1 + 5 )( 7.5 = frac{A}{2} + 5 )( frac{A}{2} = 2.5 )( A = 5 )Therefore, the closed-form expression is:( b_n = 5 left( frac{1}{2} right)^n + 5 )Simplify:( b_n = 5 left( frac{1}{2^n} right) + 5 )( b_n = 5 + frac{5}{2^n} )Wait, let me check this with the earlier values.For n=1: ( 5 + 5/2 = 5 + 2.5 = 7.5 ) million, which is correct.For n=2: ( 5 + 5/4 = 5 + 1.25 = 6.25 ) million, which matches.For n=3: ( 5 + 5/8 = 5 + 0.625 = 5.625 ) million, which also matches.Great, so that seems correct.But wait, the problem mentions that the profit after renovation excludes the investment. The investment is a one-time 6 million yuan at the beginning of 2016. So, does that affect the annual profit? Or is the 7.5 million already excluding the investment?Reading the problem again: "excluding the investment for technical renovation, the profit for 2016 is expected to be 7.5 million yuan..." So, yes, ( b_n ) is already excluding the investment. Therefore, the 6 million is a one-time cost at the beginning of 2016, but ( b_n ) is the annual profit after that, so we don't need to subtract anything else from ( b_n ).So, summarizing part (1):( a_n = 5 - 2n ) million yuan.( b_n = 5 + frac{5}{2^n} ) million yuan.Wait, but in the initial problem statement, the profit after renovation is 7.5 million in 2016, which is n=1. So, when n=1, ( b_1 = 5 + 5/2 = 7.5 ), which is correct. So, the formula is correct.**Problem (2):** Now, I need to find the cumulative net profit without renovation, ( A_n ), and the cumulative profit after renovation, ( B_n ).Starting with ( A_n ). This is the sum of ( a_n ) from n=1 to n. Since ( a_n ) is an arithmetic sequence, the sum of the first n terms of an arithmetic sequence is given by:( S_n = frac{n}{2} (a_1 + a_n) )We already have ( a_n = 5 - 2n ), and ( a_1 = 5 - 2(1) = 3 ).So,( A_n = frac{n}{2} (3 + (5 - 2n)) )Simplify inside the parentheses:( 3 + 5 - 2n = 8 - 2n )So,( A_n = frac{n}{2} (8 - 2n) )( A_n = frac{n}{2} times 2(4 - n) )( A_n = n(4 - n) )( A_n = 4n - n^2 )Wait, let me check with n=1: 4(1) - 1^2 = 4 - 1 = 3, which is correct.n=2: 8 - 4 = 4, which is 3 + 1 = 4, correct.n=3: 12 - 9 = 3, which is 3 + 1 + (-1) = 3, correct.Wait, but in reality, the profit can't be negative, but the problem doesn't specify stopping, so we just go with the formula.Now, for ( B_n ), the cumulative profit after renovation. This includes the annual profits ( b_n ) minus the one-time investment of 6 million yuan at the beginning of 2016.So, ( B_n = sum_{k=1}^{n} b_k - 6 )We already have ( b_n = 5 + frac{5}{2^n} ), so:( B_n = sum_{k=1}^{n} left(5 + frac{5}{2^k}right) - 6 )( B_n = 5n + 5 sum_{k=1}^{n} frac{1}{2^k} - 6 )The sum ( sum_{k=1}^{n} frac{1}{2^k} ) is a finite geometric series with first term ( a = 1/2 ) and common ratio ( r = 1/2 ). The sum is:( S_n = a frac{1 - r^n}{1 - r} = frac{1}{2} frac{1 - (1/2)^n}{1 - 1/2} = frac{1}{2} frac{1 - (1/2)^n}{1/2} = 1 - (1/2)^n )So,( B_n = 5n + 5(1 - (1/2)^n) - 6 )Simplify:( B_n = 5n + 5 - 5(1/2)^n - 6 )( B_n = 5n - 1 - 5(1/2)^n )Let me check this with n=1:( B_1 = 5(1) - 1 - 5(1/2) = 5 - 1 - 2.5 = 1.5 ) million yuan.But wait, the first year's profit after renovation is 7.5 million, minus the 6 million investment, so 1.5 million. That's correct.For n=2:( B_2 = 5(2) - 1 - 5(1/4) = 10 - 1 - 1.25 = 7.75 ) million.Which is 1.5 (from n=1) + 6.25 (from n=2) = 7.75, correct.For n=3:( B_3 = 15 - 1 - 5(1/8) = 14 - 0.625 = 13.375 ) million.Which is 7.75 + 5.625 = 13.375, correct.So, the formula for ( B_n ) is:( B_n = 5n - 1 - frac{5}{2^n} )Alternatively, we can write it as:( B_n = 5n - 1 - 5 left( frac{1}{2} right)^n )**Problem (3):** Now, I need to find how many years must pass from 2016 for the cumulative profit after renovation (( B_n )) to exceed the cumulative profit without renovation (( A_n )).So, we need to find the smallest integer n such that ( B_n > A_n ).From part (2):( A_n = 4n - n^2 )( B_n = 5n - 1 - frac{5}{2^n} )Set up the inequality:( 5n - 1 - frac{5}{2^n} > 4n - n^2 )Simplify:( 5n - 1 - frac{5}{2^n} - 4n + n^2 > 0 )( n^2 + n - 1 - frac{5}{2^n} > 0 )So, we need to solve for n in:( n^2 + n - 1 - frac{5}{2^n} > 0 )This is a bit tricky because it's a mix of polynomial and exponential terms. Let's try plugging in integer values of n starting from 1 until the inequality holds.n=1:( 1 + 1 - 1 - 5/2 = 1 - 2.5 = -1.5 < 0 )n=2:( 4 + 2 - 1 - 5/4 = 5 - 1.25 = 3.75 > 0 )Wait, that's positive. But let me double-check the calculations.Wait, n=2:( A_2 = 4(2) - 2^2 = 8 - 4 = 4 )( B_2 = 5(2) - 1 - 5/4 = 10 - 1 - 1.25 = 7.75 )So, 7.75 > 4, which is true. So, n=2 is the answer? But that seems too soon. Let me check n=1 again.n=1:( A_1 = 4(1) - 1^2 = 4 - 1 = 3 )( B_1 = 5(1) - 1 - 5/2 = 5 - 1 - 2.5 = 1.5 )So, 1.5 < 3, so n=1 doesn't satisfy.n=2: 7.75 > 4, so it's true.Wait, but the problem says "how many years must pass from 2016". So, if n=2 corresponds to 2017, then it's 2 years after 2016, i.e., 2018? Wait, no, n=1 is 2016, n=2 is 2017, so n=2 is the second year, so 2 years after 2016 would be 2018. But the cumulative profit after renovation exceeds without renovation at n=2, which is 2017.But let me check the cumulative profits:At n=1 (2016):Without renovation: 3 millionAfter renovation: 1.5 millionSo, 1.5 < 3At n=2 (2017):Without renovation: 3 + 1 = 4 millionAfter renovation: 1.5 + 6.25 = 7.75 million7.75 > 4, so yes, at n=2, the cumulative profit after renovation exceeds without renovation.But wait, the problem says "how many years must pass from 2016". So, if n=2 corresponds to 2017, which is 1 year after 2016, but the cumulative profit at the end of 2017 (n=2) is already higher. So, does that mean 1 year must pass? Or is it 2 years?Wait, n=1 is 2016, n=2 is 2017, so the cumulative profit after 2 years (n=2) is higher. So, the number of years that must pass from 2016 is 2 years, meaning by the end of 2018, but wait, no, n=2 is 2017, which is 1 year after 2016.Wait, this is confusing. Let me clarify.If n=1 is 2016, then n=2 is 2017, which is 1 year after 2016. So, the cumulative profit after 1 year (n=2) is higher. So, the answer would be 1 year must pass from 2016, meaning by the end of 2017.But let me check the cumulative profits again.At n=1 (2016):Without renovation: 3 millionAfter renovation: 1.5 millionAt n=2 (2017):Without renovation: 3 + 1 = 4 millionAfter renovation: 1.5 + 6.25 = 7.75 millionSo, at the end of 2017 (n=2), the cumulative profit after renovation is higher. So, the number of years that must pass from 2016 is 1 year, because after 1 year (i.e., by the end of 2017), the cumulative profit after renovation exceeds without renovation.But wait, the problem says "how many years must pass from 2016". So, if n=2 corresponds to 2017, which is 1 year after 2016, then the answer is 1 year.But let me check n=3 to be sure.n=3:Without renovation: 4 + (-1) = 3 million (Wait, no, A_n = 4n - n^2, so for n=3, 12 - 9 = 3 million.After renovation: 7.75 + 5.625 = 13.375 million.So, 13.375 > 3, which is true, but we already saw that at n=2, it's true.So, the smallest n where B_n > A_n is n=2, which is 1 year after 2016.But wait, let me double-check the inequality:( n^2 + n - 1 - frac{5}{2^n} > 0 )For n=1:1 + 1 - 1 - 5/2 = 1 - 2.5 = -1.5 < 0n=2:4 + 2 - 1 - 5/4 = 5 - 1.25 = 3.75 > 0So, yes, n=2 is the smallest integer where the inequality holds.Therefore, the number of years that must pass from 2016 is 1 year, meaning by the end of 2017.But wait, the problem might be considering the number of full years after 2016, so n=2 is 2017, which is 1 year after 2016. So, the answer is 1 year.But let me think again. If n=1 is 2016, then n=2 is 2017, which is 1 year after 2016. So, the cumulative profit after renovation exceeds without renovation after 1 year.But let me check the cumulative profits again:At n=2 (2017):Without renovation: 3 (2016) + 1 (2017) = 4 millionAfter renovation: 1.5 (2016) + 6.25 (2017) = 7.75 millionYes, 7.75 > 4, so after 1 year (n=2), it's true.Therefore, the answer is 1 year must pass from 2016.But wait, the problem might be considering the number of years starting from 2016 as n=1, so the answer is n=2, which is 2 years from 2016, but that would be 2018. But the cumulative profit at n=2 (2017) is already higher.I think the confusion is about whether n=1 is 2016 or 2017. According to the problem, n=1 is 2016. So, the number of years that must pass from 2016 is n-1. So, if n=2 is 2017, then 1 year has passed.But the problem says "how many years must pass from 2016", so if n=2 is 2017, then 1 year has passed. So, the answer is 1 year.But let me check the problem statement again:"(3) Based on the above prediction, how many years must pass from 2016 for the cumulative profit after technical renovation to exceed the cumulative profit without technical renovation?"So, it's asking for the number of years after 2016, so if the cumulative profit exceeds in 2017, which is 1 year after 2016, then the answer is 1 year.But in the initial calculation, n=2 corresponds to 2017, which is 1 year after 2016. So, the answer is 1 year.But wait, let me check the cumulative profits again:At n=1 (2016):Without renovation: 3 millionAfter renovation: 1.5 millionAt n=2 (2017):Without renovation: 3 + 1 = 4 millionAfter renovation: 1.5 + 6.25 = 7.75 millionSo, at the end of 2017, which is 1 year after 2016, the cumulative profit after renovation is higher.Therefore, the answer is 1 year.But wait, the problem might be considering the number of full years, so if the cumulative profit exceeds during the second year, it's after 1 year has passed.Yes, I think that's correct.But let me check n=3 to be thorough.At n=3 (2018):Without renovation: 4 + (-1) = 3 million (Wait, no, A_n = 4n - n^2, so for n=3, 12 - 9 = 3 million.After renovation: 7.75 + 5.625 = 13.375 million.So, 13.375 > 3, which is true, but we already saw that at n=2, it's true.Therefore, the smallest n where B_n > A_n is n=2, which is 1 year after 2016.So, the answer is 1 year must pass from 2016.But wait, let me make sure I didn't make a mistake in the inequality.The inequality was:( n^2 + n - 1 - frac{5}{2^n} > 0 )For n=1: 1 + 1 - 1 - 5/2 = -1.5 < 0n=2: 4 + 2 - 1 - 5/4 = 5 - 1.25 = 3.75 > 0So, yes, n=2 is the smallest integer where the inequality holds, which corresponds to 1 year after 2016.Therefore, the answer is 1 year.But wait, in the initial problem statement, the cumulative profit after renovation is B_n, which includes the 6 million investment. So, the first year's cumulative profit after renovation is 1.5 million, which is less than without renovation (3 million). The second year's cumulative profit is 7.75 million, which is more than without renovation (4 million). So, it takes 2 years (n=2) for the cumulative profit after renovation to exceed without renovation.But wait, n=2 corresponds to 2017, which is 1 year after 2016. So, the number of years that must pass from 2016 is 1 year.I think that's correct.But to be absolutely sure, let me check the cumulative profits:At the end of 2016 (n=1):Without renovation: 3 millionAfter renovation: 1.5 millionAt the end of 2017 (n=2):Without renovation: 3 + 1 = 4 millionAfter renovation: 1.5 + 6.25 = 7.75 millionSo, at the end of 2017, which is 1 year after 2016, the cumulative profit after renovation exceeds without renovation.Therefore, the answer is 1 year must pass from 2016.But wait, the problem might be considering the number of full years, so if the cumulative profit exceeds during the second year, it's after 1 year has passed.Yes, that's correct.So, the final answer is 1 year.
question:Keanu's motorcycle can store 8 liters of gasoline. If his destination is some miles away and his motorcycle consumes 8 liters of gasoline per 40 miles, Keanu has to refill his motorcycle with gasoline 14 times for a round trip. How far is Keanu's destination?
answer:First, I need to determine the total amount of gasoline Keanu uses for the round trip. Since he refills his motorcycle 14 times and each refill is 8 liters, the total gasoline used is 14 multiplied by 8 liters, which equals 112 liters.Next, I'll calculate the total distance Keanu can travel with 112 liters of gasoline. Given that his motorcycle consumes 8 liters of gasoline per 40 miles, I can find out how many 40-mile segments he can travel with 112 liters by dividing 112 liters by 8 liters per 40 miles. This gives me 14 segments of 40 miles each.Multiplying the number of segments by the distance per segment, 14 multiplied by 40 miles, equals 560 miles. This is the total distance for the round trip.Finally, to find the one-way distance to Keanu's destination, I'll divide the total round trip distance by 2. So, 560 miles divided by 2 equals 280 miles.
question:Given the function ( f(x) ) satisfies ( f(x+y) = f(x) + f(y) ) for any ( x, y in mathbb{R} ):(1) Find the value of ( f(0) ).(2) Prove that ( f(x) ) is an odd function.
answer:Okay, so I have this function ( f(x) ) that satisfies the equation ( f(x + y) = f(x) + f(y) ) for any real numbers ( x ) and ( y ). I need to find the value of ( f(0) ) and prove that ( f(x) ) is an odd function. Hmm, let's start with the first part.First, to find ( f(0) ), I think I can plug in some specific values for ( x ) and ( y ) into the given equation. Maybe if I set both ( x ) and ( y ) to 0, that should help. So, substituting ( x = 0 ) and ( y = 0 ), the equation becomes:( f(0 + 0) = f(0) + f(0) )Simplifying the left side, ( f(0 + 0) ) is just ( f(0) ). So, the equation now is:( f(0) = f(0) + f(0) )Hmm, that's interesting. If I subtract ( f(0) ) from both sides to solve for ( f(0) ), I get:( f(0) - f(0) = f(0) + f(0) - f(0) )Which simplifies to:( 0 = f(0) )So, that means ( f(0) = 0 ). Okay, that wasn't too bad. I think that's the answer for the first part.Now, moving on to the second part: proving that ( f(x) ) is an odd function. An odd function satisfies the property ( f(-x) = -f(x) ) for all ( x ). So, I need to show that ( f(-x) = -f(x) ).Let me think about how to use the given functional equation to show this. Maybe I can set ( y = -x ) in the equation ( f(x + y) = f(x) + f(y) ). Let's try that.Substituting ( y = -x ), we get:( f(x + (-x)) = f(x) + f(-x) )Simplifying the left side, ( x + (-x) ) is 0, so:( f(0) = f(x) + f(-x) )But from the first part, we already know that ( f(0) = 0 ). So, substituting that in:( 0 = f(x) + f(-x) )If I solve for ( f(-x) ), I subtract ( f(x) ) from both sides:( f(-x) = -f(x) )And there we go! That's exactly the property of an odd function. So, ( f(x) ) is indeed an odd function.Wait, let me double-check my steps to make sure I didn't make any mistakes. For the first part, plugging in ( x = 0 ) and ( y = 0 ) seems straightforward, and the algebra checks out. For the second part, substituting ( y = -x ) is a common technique in these types of problems, and it leads directly to the conclusion that ( f(-x) = -f(x) ). Yeah, I think I did it right.So, summarizing my findings:1. ( f(0) = 0 )2. ( f(-x) = -f(x) ), which means ( f(x) ) is an odd function.I think that's all there is to it. It wasn't too complicated once I broke it down step by step. I just needed to use the given functional equation and plug in specific values to derive the required properties.
question:Consider a set T of integers. Removing the largest integer from T results in an average of 29 for the remaining integers. If the smallest integer is also removed, the average of the remaining integers becomes 33. If the largest integer is then added back, the average becomes 38. The largest integer is 80 more than the smallest integer. Determine the average value of all integers in set T.A) 33.7B) 33.8C) 33.9D) 34.0E) 34.1
answer:Okay, so I have this problem about a set of integers, T. The problem gives me several conditions about removing the largest and smallest integers and how the average changes each time. I need to find the average value of all integers in set T. Hmm, let me try to break this down step by step.First, let me list out the given information:1. Removing the largest integer from T results in an average of 29 for the remaining integers.2. If the smallest integer is also removed (so now both the largest and smallest are removed), the average becomes 33.3. If the largest integer is then added back (so now only the smallest is removed), the average becomes 38.4. The largest integer is 80 more than the smallest integer.I need to find the average value of all integers in T. Let me denote the set T as {b₁, b₂, ..., bₘ} where b₁ is the smallest integer and bₘ is the largest integer. So, the set is ordered from smallest to largest.Let me assign some variables to make this clearer:- Let m be the number of integers in set T.- Let S be the sum of all integers in T.From the first condition, when we remove the largest integer, bₘ, the average of the remaining integers is 29. So, the sum of the remaining integers is 29*(m-1). Therefore, we can write:S - bₘ = 29*(m - 1) ...(1)From the second condition, when we remove both the largest and the smallest integers, the average becomes 33. So, the sum of the remaining integers is 33*(m - 2). Therefore:S - bₘ - b₁ = 33*(m - 2) ...(2)From the third condition, when we add back the largest integer after removing the smallest, the average becomes 38. So, the sum of the remaining integers (which are all except the smallest) is 38*(m - 1). Therefore:S - b₁ = 38*(m - 1) ...(3)Also, the fourth condition tells us that the largest integer is 80 more than the smallest:bₘ = b₁ + 80 ...(4)So, now I have four equations:1. S - bₘ = 29*(m - 1)2. S - bₘ - b₁ = 33*(m - 2)3. S - b₁ = 38*(m - 1)4. bₘ = b₁ + 80I need to solve these equations to find S and m, and then compute the average S/m.Let me see how I can manipulate these equations.First, from equation (1):S = 29*(m - 1) + bₘ ...(1a)From equation (3):S = 38*(m - 1) + b₁ ...(3a)So, both expressions equal S. Therefore, I can set them equal to each other:29*(m - 1) + bₘ = 38*(m - 1) + b₁Simplify this:29m - 29 + bₘ = 38m - 38 + b₁Bring like terms together:bₘ - b₁ = 38m - 38 - 29m + 29Simplify the right side:bₘ - b₁ = 9m - 9But from equation (4), we know that bₘ - b₁ = 80. Therefore:80 = 9m - 9Solve for m:9m = 80 + 9 = 89m = 89 / 9 ≈ 9.888...Wait, m should be an integer because it's the number of integers in the set. Hmm, 89 divided by 9 is about 9.888, which is not an integer. That doesn't make sense. Did I make a mistake somewhere?Let me check my steps again.From equation (1a): S = 29*(m - 1) + bₘFrom equation (3a): S = 38*(m - 1) + b₁Setting them equal:29*(m - 1) + bₘ = 38*(m - 1) + b₁Expanding:29m - 29 + bₘ = 38m - 38 + b₁Bring variables to one side:bₘ - b₁ = 38m - 38 - 29m + 29Simplify:bₘ - b₁ = 9m - 9From equation (4): bₘ - b₁ = 80So, 80 = 9m - 99m = 89m = 89/9 ≈ 9.888...Hmm, same result. So, m is not an integer. That can't be. Maybe I made a wrong assumption somewhere.Wait, let me check the equations again.From equation (1): S - bₘ = 29*(m - 1)From equation (2): S - bₘ - b₁ = 33*(m - 2)From equation (3): S - b₁ = 38*(m - 1)From equation (4): bₘ = b₁ + 80Let me try another approach. Maybe express S from equation (1) and substitute into equation (2).From equation (1): S = 29*(m - 1) + bₘPlug into equation (2):29*(m - 1) + bₘ - b₁ = 33*(m - 2)Simplify:29m - 29 + bₘ - b₁ = 33m - 66Bring variables to one side:bₘ - b₁ = 33m - 66 - 29m + 29Simplify:bₘ - b₁ = 4m - 37But from equation (4): bₘ - b₁ = 80So, 80 = 4m - 374m = 80 + 37 = 117m = 117 / 4 = 29.25Wait, that's even worse. m is 29.25? That can't be. Clearly, something is wrong here.Wait, maybe I made a mistake in substituting.Let me try again.From equation (1): S = 29*(m - 1) + bₘFrom equation (2): S - bₘ - b₁ = 33*(m - 2)So, substitute S from equation (1) into equation (2):29*(m - 1) + bₘ - bₘ - b₁ = 33*(m - 2)Simplify:29*(m - 1) - b₁ = 33*(m - 2)So,29m - 29 - b₁ = 33m - 66Bring variables to one side:- b₁ = 33m - 66 - 29m + 29Simplify:- b₁ = 4m - 37So,b₁ = -4m + 37Hmm, interesting. So, the smallest integer is expressed in terms of m.From equation (4): bₘ = b₁ + 80So,bₘ = (-4m + 37) + 80 = -4m + 117Now, from equation (3): S - b₁ = 38*(m - 1)But S = 29*(m - 1) + bₘ, from equation (1a)So,29*(m - 1) + bₘ - b₁ = 38*(m - 1)Substitute bₘ and b₁ from above:29*(m - 1) + (-4m + 117) - (-4m + 37) = 38*(m - 1)Simplify:29m - 29 -4m + 117 + 4m - 37 = 38m - 38Combine like terms:(29m -4m +4m) + (-29 + 117 -37) = 38m - 38Simplify:29m + 51 = 38m - 38Bring variables to one side:51 + 38 = 38m -29m89 = 9mSo,m = 89 / 9 ≈ 9.888...Again, same result. Hmm, m is not an integer. That suggests that perhaps my initial equations are incorrect or I misinterpreted the problem.Wait, let me reread the problem statement to make sure I understood it correctly."Removing the largest integer from T results in an average of 29 for the remaining integers. If the smallest integer is also removed, the average of the remaining integers becomes 33. If the largest integer is then added back, the average becomes 38. The largest integer is 80 more than the smallest integer."Wait, so step by step:1. Start with set T, remove largest, average is 29.2. From the resulting set, remove the smallest, average becomes 33.3. Then, add back the largest, average becomes 38.So, let me clarify the steps:- Original set: T, size m, sum S.- After removing largest (bₘ), we have m-1 elements, sum S - bₘ, average 29.- Then, from this set (which has m-1 elements), remove the smallest (which is b₁), so now we have m-2 elements, sum S - bₘ - b₁, average 33.- Then, add back the largest (bₘ), so now we have m-1 elements again, sum S - b₁, average 38.So, the third step is adding back the largest to the set that had both largest and smallest removed, resulting in a set with m-1 elements (all except the smallest). So, average 38.So, my equations seem correct:1. S - bₘ = 29*(m - 1)2. S - bₘ - b₁ = 33*(m - 2)3. S - b₁ = 38*(m - 1)4. bₘ = b₁ + 80So, perhaps the issue is that m is not an integer, but the problem says T is a set of integers, so m must be an integer. Therefore, maybe I need to adjust my equations or find another way.Wait, perhaps I can express S in terms of m and then find m such that S is an integer as well, since all elements are integers.From equation (1a): S = 29*(m - 1) + bₘFrom equation (3a): S = 38*(m - 1) + b₁From equation (4): bₘ = b₁ + 80So, substituting bₘ into equation (1a):S = 29*(m - 1) + b₁ + 80But from equation (3a): S = 38*(m - 1) + b₁So,29*(m - 1) + b₁ + 80 = 38*(m - 1) + b₁Simplify:29m - 29 + 80 = 38m - 38So,29m + 51 = 38m - 38Bring variables to one side:51 + 38 = 38m -29m89 = 9mm = 89/9 ≈ 9.888...Same result again. Hmm.Wait, maybe I can consider that m must be 10, since 89/9 is approximately 9.888, which is close to 10. Let me test m=10.If m=10, then from equation (4m - 37) = b₁:Wait, earlier I had:From equation (2): b₁ = -4m + 37So, if m=10,b₁ = -4*10 + 37 = -40 + 37 = -3Then, bₘ = b₁ + 80 = -3 + 80 = 77Now, from equation (1a): S = 29*(10 - 1) + bₘ = 29*9 + 77 = 261 + 77 = 338From equation (3a): S = 38*(10 - 1) + b₁ = 38*9 + (-3) = 342 - 3 = 339Wait, but S can't be both 338 and 339. That's a contradiction. So, m=10 doesn't work.Hmm, maybe m=9?If m=9,From equation (2): b₁ = -4*9 + 37 = -36 + 37 = 1Then, bₘ = 1 + 80 = 81From equation (1a): S = 29*(9 - 1) + 81 = 29*8 + 81 = 232 + 81 = 313From equation (3a): S = 38*(9 - 1) + 1 = 38*8 + 1 = 304 + 1 = 305Again, S is inconsistent: 313 vs 305. Doesn't work.Hmm, maybe m=11?From equation (2): b₁ = -4*11 + 37 = -44 + 37 = -7bₘ = -7 + 80 = 73From equation (1a): S = 29*(11 -1) + 73 = 29*10 +73=290+73=363From equation (3a): S=38*(11-1)+(-7)=38*10 -7=380-7=373Again, inconsistent.Wait, so m=89/9≈9.888, but m must be integer. Maybe the problem is designed such that m is not integer? But that can't be, since m is the number of integers in the set.Wait, perhaps I made a wrong assumption in the equations. Let me check again.From the first condition: Removing the largest, average 29. So, sum is 29*(m-1).From the second condition: Removing both largest and smallest, average 33. So, sum is 33*(m-2).From the third condition: Removing only the smallest, average 38. So, sum is 38*(m-1).Wait, perhaps I misapplied the third condition. Let me think.After removing the largest and smallest, we have m-2 elements with sum 33*(m-2). Then, adding back the largest, we have m-1 elements, sum is 33*(m-2) + bₘ, and the average is 38. So, the sum is 38*(m-1).Therefore, 33*(m-2) + bₘ = 38*(m-1)So, that's another equation.Wait, maybe I should use this instead of equation (3). Let me try that.So, equation (3) can be rewritten as:33*(m - 2) + bₘ = 38*(m - 1)So,33m - 66 + bₘ = 38m - 38Bring variables to one side:bₘ = 38m - 38 -33m +66Simplify:bₘ = 5m +28So, from equation (4): bₘ = b₁ +80So,b₁ +80 =5m +28Therefore,b₁ =5m +28 -80=5m -52So, now, from equation (1): S - bₘ =29*(m -1)But S = sum of all elements, which is also equal to sum after removing smallest and largest plus b₁ and bₘ.Wait, from equation (2): S - bₘ - b₁=33*(m -2)So,S =33*(m -2) + bₘ + b₁But from equation (1): S =29*(m -1) + bₘTherefore,29*(m -1) + bₘ =33*(m -2) + bₘ + b₁Simplify:29m -29 =33m -66 + b₁Bring variables to one side:-29 +66 =33m -29m + b₁37=4m + b₁But from earlier, b₁=5m -52So,37=4m +5m -5237=9m -529m=37+52=89m=89/9≈9.888...Same result again. So, m=89/9, which is not integer. Hmm.Wait, maybe I need to consider that m must be integer, so perhaps the problem is designed such that m is 10, and we have some rounding or something? But the answer choices are decimals, so maybe the average is a decimal.Wait, but the sum S must be integer because all elements are integers. So, if m=10, S must be integer. Let me try m=10 again.From equation (4m -37)=b₁, which was from earlier:Wait, earlier I had:From equation (2): b₁ = -4m +37So, for m=10, b₁=-3Then, bₘ=77From equation (1a): S=29*(10-1)+77=261+77=338From equation (3a): S=38*(10-1)+(-3)=342-3=339But S can't be both 338 and 339. Contradiction.Wait, but if m=10, and S is 338 or 339, but S must be consistent.Wait, perhaps the problem allows for non-integer averages, but the sum must be integer. So, maybe m=10, S=339, which is 339/10=33.9 average.But let me check if S=339 works.From equation (1): S - bₘ=29*(10-1)=261So, 339 - bₘ=261 => bₘ=339-261=78From equation (4): bₘ=b₁+80 =>78=b₁+80 =>b₁= -2From equation (2): S - bₘ -b₁=33*(10-2)=264So, 339 -78 -(-2)=339 -78 +2=263But 263≠264. Hmm, discrepancy of 1.Wait, maybe m=10, S=339, bₘ=78, b₁=-2Then, S -bₘ=339-78=261=29*9=261, which is correct.S -bₘ -b₁=339-78-(-2)=263, which should be 33*8=264. It's off by 1.Hmm, close but not exact.Alternatively, maybe m=10, S=340.Then, from equation (1): S -bₘ=29*9=261 => bₘ=340-261=79From equation (4): b₁=79-80=-1From equation (2): S -bₘ -b₁=340-79-(-1)=340-79+1=262Which should be 33*8=264. Still off by 2.Hmm.Wait, maybe m=10, S=338.From equation (1): bₘ=338-261=77From equation (4): b₁=77-80=-3From equation (2): S -bₘ -b₁=338-77-(-3)=338-77+3=264Which is exactly 33*8=264. Perfect.So, S=338, m=10, bₘ=77, b₁=-3But from equation (3): S -b₁=338 - (-3)=341Which should be 38*(10-1)=38*9=342But 341≠342. Off by 1.Hmm, so close.Wait, maybe m=10, S=339, bₘ=78, b₁=-2Then, S -b₁=339 - (-2)=341, which should be 38*9=342. Off by 1.Alternatively, m=10, S=340, bₘ=79, b₁=-1S -b₁=340 - (-1)=341, which is still off by 1 from 342.Hmm, seems like there's a discrepancy of 1 in all cases. Maybe the problem allows for some rounding, or perhaps I made a mistake in the equations.Wait, let me try to use the equations differently.From equation (1): S =29*(m -1) + bₘFrom equation (3): S =38*(m -1) + b₁Set equal:29*(m -1) + bₘ =38*(m -1) + b₁From equation (4): bₘ =b₁ +80So,29m -29 + b₁ +80 =38m -38 + b₁Simplify:29m +51 =38m -38So,51 +38=38m -29m89=9mm=89/9≈9.888...So, m≈9.888, which is not integer.But since m must be integer, perhaps the problem is designed such that m=10, and the sum S is 339, which gives an average of 33.9, which is one of the options.Alternatively, maybe the problem allows for m=89/9, but that doesn't make sense because m must be integer.Wait, perhaps I need to consider that the set T has m elements, and when we remove the largest, we have m-1 elements, and so on. So, m must be at least 3, since we remove two elements.But given that m=89/9≈9.888, which is close to 10, maybe the problem expects m=10, and the sum S=339, which gives an average of 33.9.Alternatively, maybe I need to adjust the equations to account for the fact that m is not integer, but that seems unlikely.Wait, let me try to express S in terms of m.From equation (1a): S=29m -29 +bₘFrom equation (3a): S=38m -38 +b₁From equation (4): bₘ=b₁ +80So, substitute bₘ into equation (1a):S=29m -29 +b₁ +80=29m +51 +b₁From equation (3a): S=38m -38 +b₁Set equal:29m +51 +b₁=38m -38 +b₁Cancel b₁:29m +51=38m -38So,51 +38=38m -29m89=9mm=89/9≈9.888...So, same result.Therefore, m=89/9, which is approximately 9.888, but since m must be integer, perhaps the problem is designed such that m=10, and the sum S=339, which is 33.9 average.Alternatively, maybe the problem allows for m=89/9, but that doesn't make sense because m must be integer.Wait, perhaps the problem is designed such that m=10, and the sum S=339, which is 33.9 average, which is option C.So, despite the inconsistency in the equations, the answer is likely 33.9.Therefore, the average value of all integers in set T is 33.9.
question:Evaluate the expression: (-2)^{3^{2}} + 2^{3^2}.A. -1024B. -512C. 0D. 512E. 1024
answer:First, I need to evaluate the expression ((-2)^{3^{2}} + 2^{3^2}).I'll start by calculating the exponent (3^{2}), which equals 9.Next, I'll evaluate each term separately:- For ((-2)^{9}), since the exponent is odd, the result will be negative. Calculating ((-2)^{9}) gives (-512).- For (2^{9}), the result is (512).Finally, I'll add the two results together: (-512 + 512 = 0).Therefore, the final answer is (0).