Which angle is an x-intercept for the function y = cos(1/2x)

For the function
y = cos(1/2 x)
The x-intercept can be calculated by equating the function to zero and solving for x. So,
y = cos(1/2 x) = 0
1/2 x = arc cos 0
1/2 x = 90° +180°n
x =2 (90° +180°n)
x = 180° + 360°n
or converting to radians
x = (180° + 360° n)(π/180°)
x = π + 2π n
where n is any whole number

if n = 0
x = π

Therefore, the x-intercept is π or π+2π n

Where are the following equations?

Ican't do any of the other stuff, but i can get you started. the answer, i believe, is $2.50.