$\frac{x^2}{4}\left(\pi-\cos ^{-1} x^2\right)+\frac{1}{4} \sqrt{1-x^2}+C$

$\frac{x^2}{4}\left(\pi-\cos ^{-1} x^2\right)+\frac{1}{4} \sqrt{1-x^4}+C$

$\frac{x^2}{4}\left(\pi+\cos ^{-1} x^2\right)-\frac{1}{4} \sqrt{1-x^4}+C$

$\frac{x^2}{4}\left(\pi+\cos ^{-1} x^2\right)-\frac{1}{4} \sqrt{1-x^2}+C$

$\frac{1}{2+\tan x}+C$

$-\frac{1}{2 \tan x+1}+C$

$\frac{\cos x}{\cos x+2 \sin x}+C$

$-\frac{\cos x}{2 \cos x+\sin x}+C$

0

1

3

2

$-e^{-x}\left(x^3-x^2+5 x-1\right)+C$

$e^{-x}\left(x^3-x^2+5 x-1\right)+C$

$e^{-x}\left(x^3+x^2+5 x+1\right)+C$

$-e^{-x}\left(x^3+x^2+5 x+1\right)+C$