MHB How Do You Solve for C in This Integral Equation?

[scottshannon]

Have added attachment. Can anyone show me how to approach this problem? Thank you...

 

[Dethrone]

Hi scottshannon!

We have $\int_1^{f(x)}g(t) \,dt =\frac{1}{3}\left(x^{3/2}-8\right)$ with $f^{-1}(x)=g(x)$. Applying the fundamental theorem of calculus on both sides:
$$g(f(x))\cdot f'(x)=\frac{1}{2}\sqrt{x}$$
$$x \cdot f'(x) =\frac{1}{2}\sqrt{x}$$
$$f'(x)=\frac{1}{2\sqrt{x}}$$
Solving the resulting by integrating:
$$f(x)=\sqrt{x}+C$$

Now, how may we solve for $C$?