Prove that (\cos A+\sin A)(\cos 2A+\sin 2A)=\cos A+\sin 3A

Gregory Emery

Gregory Emery

Answered question

2022-01-17

Prove that (cosA+sinA)(cos2A+sin2A)=cosA+sin3A

Answer & Explanation

soanooooo40

soanooooo40

Beginner2022-01-18Added 35 answers

Use following facts:
cosAsin2A+sinAcos2A=sin(A+2A)=sin3A
cosAcos2A+sinAsin2A=cos(2AA)=cosA

Do you have a similar question?

Recalculate according to your conditions!

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?