# Thread: product and quotient of cos and sin

1. ## product and quotient of cos and sin

I have the quantities 2(cos pi/3 + i sin pi/3) and 4(cos pi/4 + i sin pi/4) and am looking to see if I have the correct product and quotient respectively.
I come up with:
8(cos 7pi/12 + i sin 7pi/12) and 1/2(cos 7pi/12 + i sin 7pi/12)
correct or not quite? Thanks for the help in advance!

2. How did you get these answers?

Did you use these methods Complex numbers : De Moivre's theorem : Multiplication using polar form ?

3. ## sin and cos

yeah something like that...