Question

How do you find the value of `cos(pi/3)`?

Answer 1

`cos(pi/3)=color(green)(1/2)`

Explanation:

Consider an equilateral triangle with sides of length `2`
Since the interior angles are all equal and have a sum of `pi` radians,
each angle is `pi/3`

Dividing the triangle into halves as in the image below
and remembering the definition of `cos` as `("adjacent side")/("hypotenuse")`

We see that `cos(pi/3)=1/2`