Question

What is the exact value for cos(pi/12)?

Answer 1

`sqrt(2+sqrt(3))/2`

Explanation:

`color(blue)(cos(x/2)=+-sqrt((1+cos(x))/2))`

We know that `cos(pi/6)=sqrt(3)/2`.

So, `cos(pi/12)=sqrt((1+sqrt(3)/2)/2)=sqrt((2+sqrt(3))/4)=sqrt(2+sqrt(3))/2`

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