Final answer:
The double-angle identity that can be used to verify the equation csc x sec x = 2 csc 2x is option b. sin 2x=2 sinx cosx.
Step-by-step explanation:
The double-angle identity that can be used to verify the equation csc x sec x = 2 csc 2x is option b. sin 2x=2 sinx cosx.
To verify this, we can substitute csc x = 1/sin x and sec x = 1/cos x in the equation. We get:
(1/sin x) * (1/cos x) = 2 * (1/sin 2x)
Simplifying both sides gives us (1/sin x * cos x) = 2/sin 2x, which is the same as sin 2x = 2sin x * cos x.