Prove that:
Cos²7π/8 + cos²5π/8 +cos²3π/8 + cos²π/8 = 2
Answer:



I won't explain the answer but rather show you the values of them. Once you put the value of sin and cos as indicated in the question and perform the basic Mathematics, you will get your answer.


Also, you need to understand these formulas (a part of CAST formula)





You need to understand the above-mentioned values of Trigonometric ratios at different angles to be able to solve such questions.

#SciPiTutor
#TrigonometricValue
#Trigonometry
#Mathematics