ive tried everything i could think of and cant get a proper u.

x^2 (sq.rt.(x+1)) dx

(sin x) dx/(sq.rt.(cos^3 x))

sin (sq.rt.(x+1)) dx/ (sq.rt. (x+1) from 3 to 8

they dont seem like they should cause too much problems, but for the life of me, i cant figure them out

any help is appreciated, as always