Question

Let `F(x)=int_(0)^xsqrt(1+t^2)dt` how to find `F'(x)`?

Answer 1

As `f(x) = sqrt(1+x^2)` is continuous for any `x in RR`, based on the fundamental theorem of calculus:

`d/dx (int_0^x sqrt(1+t^2)dt) = sqrt(1+x^2)`