Question

How do you find the exact value of `2cosx-secx=0` in the interval `0<=x<360`?

Answer 1

`2cosx - 1/cosx = 0`

`2cos^2x - 1 = 0`

`cos^2x= 1/2`

`cosx= +-1/sqrt(2)`

`x = 45˚, 135˚, 225˚, 315˚`

Hopefully this helps!