Hey pat for the first one do this: sub in x=2/3 tan u. for the second one do the following: sub in u=arc sin x, then you get dx= cos u du. ultimately the integrand becomes u^2 cos u . I guess u know what to do after that. foe 3rd one: hmmmmmmmmmmmmmmm wait a second. for 4th try subing in u= 3 e^(2x) -6e^x-1