Prove that:

![]()
![]()
![]()
But cos (A+B)cos(A–B)=cos2A–sin2B
Then the above equation becomes,
![]()
![]()
And ![]()
Hence the above equation becomes,
![]()
![]()
Hence proved
AI is thinking…
Couldn't generate an explanation.
Generated by AI. May contain inaccuracies — always verify with your textbook.



