Which double-angle or half-angle identity would you use to verify the following: cscxsecx=2csc2x a) cos2x=1-sin^2x b)sin2x=2sinxcosx c)tan2x=(2tanx)/(1-tan^2x) d)cos2x=2cos^2x-1

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?