Question

Solve for x on [0, 2pi) : (x-pi)/(cos^2 x) < 0

Answer 1

Note that cos²(x) > 0 for all x except x = π/2 ≞ 90° or x = 3π/2 ≞ 270°
Therefore if (x – π)/cos²(x) < 0 is true then the numerator must be negative.

x – π < 0 implies that x < π are all the solutions.

Answer 2

Thank you!