CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Prove sin(n+1)xsin(n+2)x+cos(n+1)xcos(n+2)x=cosx

Open in App
Solution

To prove:- sin(n+1)xsin(n+2)x+cos(n+1)xcos(n+2)x=cosx

Proof :

L.H.S.=
sin(n+1)xsin(n+2)x+cos(n+1)xcos(n+2)x
=cos((n+2)x(n1)x){cos(AB)=sinAsinB+cosAcosB}
=cos((n+2n1)x)
=cosx=R.H.S.
Hence proved.

flag
Suggest Corrections
thumbs-up
1
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Transformations
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon