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

Prove the following identities:
cos2π8+cos23π8+cos25π8+cos27π8=2

Open in App
Solution

L.H.S.

sin2π8+sin23π8+sin25π8+sin27π8

=sin2π8+sin23π8+sin2(π3π8)+sin2(ππ8)

=sin2π8+sin23π8+cos23π8+cos2π8

=(sin2π8+cos2π8)+(sin23π8+cos23π8)

=1+1=2

R.H.S.

flag
Suggest Corrections
thumbs-up
5
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon