1. Calculate the integrals of:

a*x*sin(bx) dx

Mr F says: Use integration by parts.
and

(x^2)(sin^2(ax)) dx

where a and b are constants. hint: use double angle formula

Mr F says: . Hint 2: Use integration by parts (twice).
2. consider the improper integral

integral from (2*sqrt(3)) to infiniti of: (24x^3)/(4+x^2)^(5/2) dx.

EDIT: Make an appropriate trigonometric substitution to convert into a proper integral. Hence determine its value.

Mr F says: Substitute .
Someone can help me with these please?