How do you find a double angle formula for sec(2x) in terms of only csc(x) and sec(x)?

##sec2x## ##=1/cos(2x)## ##=1/(cos^2x-sin^2x)## ##=1/(cos^2xsin^2x(1/sin^2x-1/cos^2x))## ##=(1/(cos^2x)1/sin^2x)/(1/sin^2x-1/cos^2x)## ##=(sec^2xcsc^2x)/(csc^2x-sec^2x)##

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