Answer:
csc²(x)
Explanation:
csc(x) = 1/sin(x)
sin²(x) + cos²(x) = 1
=> cos²(x) = 1 - sin²(x)
cos(2x) = cos²(x) - sin²(x) = (1 - sin²(x)) - sin²(x) =
= 1 - 2×sin²(x)
=> 2×sin²(x) = 1 - cos(2x)
sin²(x) = 1/2×(1-cos(2x))
=> 1 - cos(2x) = 2×(1/2×(1-cos(2x)) = 2×sin²(x)
=> 2 / (1-cos(2x)) = 2 / (2×sin²(x)) = 1/sin²(x) =
= 1/sin(x) × 1/sin(x) = csc(x)×csc(x) = csc²(x)