Asked by JD
I did post it wrong.
sin(4x)/sin(x)=4cos(x)cos(2x).
Verify the identity, please explain!
sin(4x)/sin(x)=4cos(x)cos(2x).
Verify the identity, please explain!
Answers
Answered by
Ms. Sue
Please, keep the same name when posting on Jiskha.
Answered by
drwls
It has already been explained. See Reiny's answer to your previous post.
Answered by
MathMate
For the left hand side, use
sin(4x)=2sin(2x)cos(2x)
sin(2x)=2sin(x)cos(x)
cos(2x)=cos²(x)-sin²(x)
and finally to eliminate sin²(x), use
sin²(x)=1-cos²(x)
For the right hand side, use
cos(2x)=cos²(x)-sin²(x)
and
sin²(x)=1-cos²(x)
Both sides will be expressed in terms of cos(x).
sin(4x)=2sin(2x)cos(2x)
sin(2x)=2sin(x)cos(x)
cos(2x)=cos²(x)-sin²(x)
and finally to eliminate sin²(x), use
sin²(x)=1-cos²(x)
For the right hand side, use
cos(2x)=cos²(x)-sin²(x)
and
sin²(x)=1-cos²(x)
Both sides will be expressed in terms of cos(x).
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.