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Answer
tan(2x) = 2tanx / 1 - (tan^2 (x))
using this tanx = 2 tan (x/2) / (1- tan^2 x/2)
assume tan(x/2) = t
you will get tanx = 2t/ 1-(t^2)
find secx next then find cosx, then substitute cosx value, you will get answer
