sort of like rationalizing radical expressions, multiply top and bottom by (1+cosX), giving
(1+cosX)^2
-------------
(1-cos^2X
= (1+cosX)^2/sin^2X
= [(1+cosX)/sinX]^2
= (cscX + cotX)^2
Prove
1+cos X/1-cos X = (csc X + cot X)squared
1 answer