Solve `tan x lt 2`.

Answer

`x in (n pi-pi/2, n pi+ tam^(-1) 2), n in Z`

Explanation

We know that `tan x` is periodic with period `pi`. So, check the solution on the interval `(- pi/2, pi/2)`.

It is clear from figure
`tan x lt 2` when `-pi/2 lt x lt tan^(-1) 2`
General solution is
`npi -pi/2 lt x lt n pi + tan^(1-) 2, n in Z`
`rArr n in (n pi-pi/2, n pi + tan^(-1) 2), n in Z`