Can someone show me the steps to get to the answers?

x*sin(2*x) dx;

The answer is:

1/4*sin(2*x)-1/2*x*cos(2*x)

1/(x^2*(x^2+4)) dx;

The answer is -1/8*arctan(1/2*x)-1/(4*x)

(sin*(x))/(1+cos^2*(x)) dx;

The answer is:

sin/cos^2*x-sin/cos^4*ln(1+cos^2*x)

x/(sqrt(9-x^2)) dx 0to1

The answer is:

1/(3+2*2^(1/2))