Integral Problem

Kevrad

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Dec 21, 2012
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Compute f'(1) where f(x) is defined by
f(x)=(integral Sign)sqrt[1+x^3]dx

For this problem do i just plug in 1 to sqrt[1+x^3]?
 
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Compute f'(1) where f(x) is defined by
f(x)=(integral Sign)sqrt[1+x^3]dx

For this problem do i just plug in 1 to sqrt[1+x^3]?

Yes, the derivative is the left inverse to an antiderivative. So:

\(\displaystyle \displaystyle \dfrac{d}{dx}\left( \underbrace{\int\, g(x)\, dx}_{f(x)} \right) = \underbrace{g(x)}_{f'(x)}\)
 
Compute f'(1) where f(x) is defined by
f(x)=(integral Sign)sqrt[1+x^3]dx

For this problem do i just plug in 1 to sqrt[1+x^3]?


Given: f(x)=integral of sqrt (1+x^3) dx

Thus, f'(x)=sqrt(1+x^3)
Hence, f'(1)=sqrt(1+1^3)=sqrt(2)=1.414
 
Given: f(x) = integral of sqrt (1 + x^3) dx

Thus, f'(x) = sqrt(1 + x^3)

Hence, f'(1) = sqrt(1 + 1^3) = sqrt(2) \(\displaystyle \approx\) 1.414

The equals sign was traded for the "is approximately equal to" sign.

And spacing was added for more readability.
 
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