- #1

member 731016

- Homework Statement
- Pls see the statement below

- Relevant Equations
- Binomial theorem

Why when proving trig identities,

Do we assume that r = 1 from ## rcis\theta = r[\cos\theta + i\sin\theta]##? This makes me think that this is somehow it is related the unit circle.

Note: I am trying to prove the ##cos3\theta## identity and am curious why we assume that the modulus is 1.

Many thanks!

Do we assume that r = 1 from ## rcis\theta = r[\cos\theta + i\sin\theta]##? This makes me think that this is somehow it is related the unit circle.

Note: I am trying to prove the ##cos3\theta## identity and am curious why we assume that the modulus is 1.

Many thanks!