Question

How do you solve `cos(pix)=0.5` between the interval `0<=x<2`?

Answer 1

`color(blue)(x=1/3 ,5/3)`

Explanation:

`cos(pix)=0.5`

`pix=arccos(cos(pix))=arccos(0.5)=pi/3, (5pi)/3,(7pi)/3`etc

`pix=pi/3=>x=pi/(pi3)=1/3`

`pix=(5pi)/3=>x=(5pi)/(pi3)=5/3`

`pix=(7pi)/3=>x=(7pi)/(pi3)=7/3` ( too great )

`color(blue)(x=1/3 ,5/3)`