Thread: reduction formula

hey there, first time poster, long time struggler...so i need some help with a problem.

it says to find the reduction formula for the integral (e^x)(sin x)^n in terms of the integral (e^x)(sin x)^n-2.

i know its integration by parts but i have no idea what to do for my substitutions because (sin x)^n on its own is difficult enough so how do I incorporate the e^x?

cheers!

Originally Posted by jackm7

hey there, first time poster, long time struggler...so i need some help with a problem.

it says to find the reduction formula for the integral (e^x)(sin x)^n in terms of the integral (e^x)(sin x)^n-2.

i know its integration by parts but i have no idea what to do for my substitutions because (sin x)^n on its own is difficult enough so how do I incorporate the e^x?

cheers!

Integration by parts twice. For the first use



so



and



For the second by parts



and use some identites - see how that goes.