If f(x) = $\displaystyle \int_1^x \sqrt{t^2+3}dt$ , then f`(2)=?

The integral is from 1 to x^2 but I couldn't figure out how to do that in the integral. Everything else is right.

So the answer is 4$\displaystyle \sqrt(19)$ but I got $\displaystyle \sqrt(7)$.