Calc help, please?

Question

1. Scos^3 x sin x dx; u=cos x

2. s 1/(square root of 2) sin (square root of x) and u=square root of x

3. S (3xdx)/(square root of 4x^2 +5) u=4x^2+5

4. S (x^2)/(x^3-4) dx; u=x^3 -4  

Here S means integral

Answer 1

Substitution method

1)

2)

By using parts of integration.

Answer 2

Substitution method

3)

 

4)