AJ L. answered 04/07/23
Patient and knowledgeable Calculus Tutor committed to student mastery
The Mean Value Theorem for integrals states that a function f that is continuous over the interval [a,b] has a value of c within that interval such that f'(c) = [f(b)-f(a)]/(b-a)
Given our function is f(x)=7√x over the interval [4,9] we can find the average rate of change:
f'(c) = [f(b)-f(a)]/(b-a)
f'(c) = [f(9)-f(4)]/(9-4)
f'(c) = (21-14)/5
f'(c) = 7/5
Because f'(c) = 7/(2√c), we can set this equal to 7/5 from before and solve for c:
7/(2√c) = 7/5
2√c = 5
√c = 5/2
c = 25/4
Hence, the value of c guaranteed by the Mean Value Theorem for Integrals for the function over the given interval is c = 25/4, or c = 6.2
Hope this helped!
AJ L.
04/07/23