Solve for x 2tanx - sec squared x equals 0?

Answer 1

First write everything in terms of sines and cosines.

2 sin x / cos x - (1 / cos x)2 = 0

Multiply by the common denominator, cos2x:

2 sin x cos x - 1 = 0

Solve:

2 sin x cos x = 1

sin 2x = 1

2x = pi/2, or 2x = 5pi/2, or 2x = 9pi/2...

For the first one, 2x = pi/2 --> x = pi/4.