Question

How do you solve `2 cos^2 ø - cos ø = 0`?

Answer 1

`S={pi/2 +pin, +-pi/3 +2pin}`

Explanation:

`cos phi(2cos phi-1)=0`

`cos phi =0, 2 cos phi-1=0`

`cos phi=0 or cos phi =1/2`

`phi=cos^-1 0 or phi=cos^-1 (1/2)`

`phi=pi/2 +pin, +-pi/3 +2pin`

`S={pi/2 +pin, +-pi/3 +2pin}`