Question 682945
prove following identity:
(1-cosB)/(sinB)=(sinB)/(1+cosB)
stare with left side
(1-cosB)/(sinB)
multiply both top and bottom by 1+cosB, making the denominator a difference of 2 squares
(1-cosB)/(sinB)*1+cosB/1+cosB
=(1-cos^2B)/sinB(1+cosB)
=sin^2B/(sinB(1+cosB))
=sinB/1+cosB
verified: left side=right side