Question

How to add/multiply: (sin 3theta)(sin theta) + (cos 3theta)(cos theta)? I know the first term is sin^2 but how to multiply 3theta and theta?

Answer 1

You cannot multiply trig functions if the arguments are different. So (sin 3theta)(sin theta) is NOT sin^2 3theta^2

You must use formulas to convert sin 3theta and cos 3theta to functions with an argument of theta

Answer 2

thank you