ap calculus help anyone..!!!!?

Question

if u = x^2 + 1 then integral 1 to 2 x^2/x^2+1 dx =

Answer 1

I assume your question is 2x^2 / (x^2 + 1)

Write it as (2x^2 + 2) / (x^2 + 1) - 2/(x^2 + 1)
= 2*[1 - 1/(x^2 + 1)]

The integral of this is standard:
= 2*[x - arc tan(x)] + constant

Answer 2

In t( x^2/( x^2+1) dx= Int 1 - 1(1+x^2) dx =
x - arctan x( between 1 and 2=
= 2-Arctan2 -1+pi/4 = 1+pi/4-Arctan2