Question

Question #e6719

Answer 1

`tan x = +- sqrt5/2`

Explanation:

Use the trig identity:
`1 + tan^2 x = 1/(cos^2 x)`
`cos x = 2/3` --> `cos^2 x = 4/9` --> `1/(cos^2 x) = 9/4`
`tan^2 x + 1 = 9/4`
`tan^2 x = 9/4 - 1 = 5/4`
`tan x = +- sqrt5/2`