wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

If sin x + sin2 x = 1, then write the value of cos8 x + 2 cos6 x + cos4 x.

Open in App
Solution

We have:sinx + sin2x=1 1sinx=1-sin2xsinx=cos2x 2Now, taking square of 1: sinx+sin2x 2=12 sinx 2+sin2x2+2sinx sin2x=1 sinx 2+sinx4+ 2sinx 3=1 sinx2+2sinx 3+sinx 4=1 cos2x2+2cos2x3+cos2x 4=1 cos4x+2cos6x+cos8x=1 cos8x+2cos6x+cos4x=1

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Compound Angles
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon