For the second one, completing the square is a good approach, but you don't have to use trig sub.
Upon completing the square, we get:
Let
I believe you have an ln and an arctan in your future.
Hey guys, I'm having touble inegrating:
(cosh[3t]^5)(sinh[3t]^4)
I've tried a number of things, integration by parts, using the identities and double angle formulae, substitution and a bunch of combinations of the above but cannot get the result given by The Integrator--Integrals from Mathematica which gives a hideous looking beast of an answer.
and i also can't do:
(u+3)/([u^2]+4u+8)
I believe I need to complete the square and then use a trigonometric substitution but can't figure it out, or maybe I'm getting lazy. Insight please?
Would appreciate any help.. thanks guys.
Aleks