Question

why the value of cos x repeat after an interval of 2π radian
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Answer 1

Answer:

You know sinx,cosx and tanx are periodic functions with periods 2π,2π and π respectively.i.e

sin(2π+θ)=sinθ

cos(2π+θ)=cosθ

tan(π+θ)=tanθ.

This is why they repeats their values after their periods.

here is periodic table above...

hope it helps you..!!