Guest

If sin x + sin2x + sin3x= 1, then cos6x-4cos4x+8cos2x =

If sin x + sin2x + sin3x= 1, then cos6x-4cos4x+8cos2x =

Grade:10

1 Answers

SAGAR SINGH - IIT DELHI
879 Points
12 years ago

Dear student,

It's probably not in the spirit of the question but you can just solve that cubic numerically and get sin(x) = 0.5437. Then using cos^2(x) = 1- sin^2(x) you can easily evaluate it.

The answer will be 4.

Please feel free to ask your queries here. We are all IITians and here to help you in your IIT JEE preparation.

All the best.

Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.

Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar  respectively : Click here to download the toolbar..

 

Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

sagarsingh24.iitd@gmail.com

Think You Can Provide A Better Answer ?