...Hi. I m finding hard to solve these questions

1.

integration of

(x+1)(x^2 + 2x -5)^(1/2) dx

substitution ... let u = x^2 + 2x - 5

2. integration of

x^2 / (x+2)^3 dx

u = x+2 ... x = u-2 ... du = dx

(u-2)^2 / u^3 du ... expand the numerator and divide each term by u^3

3. integration of

cos^3(x)/sin^3(x) dx

[1-sin^2(x)]/sin^3(x) * cos(x) dx

let u = sin(x)

4. integration of

(3 − sin(3x)) cos(3x) dx

3cos(3x) - sin(3x)cos(3x)

3cos(3x) - (1/2)sin(6x)