2tan x + sec x = 4cos x
(2sin+1)/cos = 4cos
2sin+1 = 4cos^2
2sin+1 = 4 - 4sin^2
4sin^2 + 2sin - 3 = 0
Now just solve the quadratic for sin x, and you can then get x.
2sin+1 = 4cos^2
2sin+1 = 4 - 4sin^2
4sin^2 + 2sin - 3 = 0
Now just solve the quadratic for sin x, and you can then get x.