Q. Answer the following True or False. For all 1<a<b, ∫abx2dx>∫abxdx. True False
Calculate Integral of x2: Let's first calculate the integral of x2 from a to b. The antiderivative of x2 is (1/3)x3. So, the definite integral from a to b is (1/3)b3−(1/3)a3.
Calculate Integral of x: Now, let's calculate the integral of x from a to b. The antiderivative of x is (1/2)x2. So, the definite integral from a to b is (1/2)b2−(1/2)a2.
Comparison of Integrals: We need to compare (31)b3−(31)a3 with (21)b2−(21)a2. Since 1 < a < b, we know that b^3 > b^2 and a^3 > a^2. Therefore, (\frac{1}{3})b^3 > (\frac{1}{2})b^2 and (\frac{1}{3})a^3 > (\frac{1}{2})a^2.
Consider Coefficients: However, we need to be careful with the comparison because the coefficients (31) and (21) affect the values.We can't directly conclude that (31)b3−(31)a3 is greater than (21)b2−(21)a2 just because b^3 > b^2 and a^3 > a^2.We need to consider the entire expression.
Analyzing Expressions: Let's analyze the expressions further.For b3 to be greater than b2, b must be greater than 1, which is given.Similarly, for a3 to be greater than a2, a must be greater than 1, which is also given.
Compare Coefficients: Now, let's compare the coefficients.(31) is less than (21), which means that for the same base, the term with the coefficient (31) will be smaller than the term with the coefficient (21).This means that we need to be cautious in our comparison because the larger exponent is paired with the smaller coefficient.
Behavior of Functions: To make a proper comparison, we can consider the behavior of the functions x2 and x as x increases.The function x2 grows faster than the function x as x increases beyond 1.This means that the area under the curve of x2 from a to b will grow more rapidly than the area under the curve of x from a to b.
Conclusion: Since the growth rate of x2 is faster than that of x, and both a and b are greater than 1, the integral of x2 from a to b will indeed be greater than the integral of x from a to b. This means that the original statement is true.