The question is somewhat poorly posed because the equation doesn't involve θ at all. I assume the author meant to use x.
sec(x) = csc(x)
By definition of secant and cosecant,
1/cos(x) = 1/sin(x)
Multiply both sides by sin(x) :
sin(x)/cos(x) = sin(x)/sin(x)
As long as sin(x) ≠ 0, this reduces to
sin(x)/cos(x) = 1
By definition of tangent,
tan(x) = 1
Solve for x :
x = arctan(1) + nπ
x = π/4 + nπ
(where n is any integer)
In the interval 0 ≤ x ≤ 2π, you get 2 solutions when n = 0 and n = 1 of
x = π/4 or x = 5π/4