prove-

cos2(pi /8) + cos2 (3pi / 8) +cos2(5pi / 8) +cos2 (7pi / 8) = 2

To prove:

Proof:

[Hence proved]

  • 58

 cospi/8 +cos3pi/8 +cospi/2+pi/8 +cospi/2+3pi/8 

=cospi/8 +cos3pi/8 +sinpi/ 8+sin3pi/8 

=2  

  • -25
What are you looking for?