Question

Select all true statements:
A) The double-angle identity for cos2A = 1 - 2sin2A.

B) Double-angle identities may be derived from angle sum identities, using (A + A) instead of (A + B) for the angle sum.

C) The double-angle identity for cos2A = 2cos2A - 1.

D) The double angle identity for sin2A = 2cos2A.