How do you prove #1/(1-cosA) + 1/(1+cosA)= 2+2cot^2A#?

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Answer 1 · 2015-04-30T17:07:46

Starting with the LHS, the sum would be

#(1+cos A +1 -cos A)/((1+cosA)(1-cosA))#

=#2/(1-cos^2A)#

= #2/sin^2A#

=#2csc^2A#

= #2(1+cot^2A)#

=#2+2cot^2A#