Please help! Studying for a test T T

[inner briar]

My subject in Calc 2 right now is about trig integrals. One main method to solve these is to use trig identities to simplify the integrand. I'm practicing right now and its the first time that I am solving a problem that has theta as 3x instead of x. The problem is "Evaluate the integral of (cos3x)^3dx" and splitting off the eq i can get (cos3x)^2 x cos3x. When theta is just x, I can just use the identity (cosx)^2 = 1-(sinx)^2 right? Is it the same when theta is 3x?

[frank summit]

1. Wait patiently for a helper to come along.
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[uneven herald]

yes

1-sin²(3x)

@inner briar

[inner briar]

thank you!

+close