trig
posted by Animesh .
If the value of sin theta =12/13 then find the value of 1cos theta/1+cos theta.

You should recognize the 51213 triangle
if sinØ = 12/13, then
cosØ = 5/13
so (1cosØ)/(1+cosØ)
= (15/13)/(1+5/13)
= (8/13) / (18/13)
= (8/13)(13/18)
=8/18 = 4/9