Question

you are given that w is an angle in the third quadrant and tan w =12/5.
Draw tha angle and calculate the exact value of cos w and sin w.
Now calculate the exact value, (no calculator), of the following.
(i) sin 1/2 w
(ii) cos 1/2 w
(iii) tan 1/2 w

Answer 1

cosw is 5/13 and sinw is 12/13 use triplet of 5,12 and 13..
rest is simple