If sin A = $\displaystyle -sqrt(17)/9$ and A is in the 3rd quadrant, find exact values of:
(i) cos A (ii) tan A (iii) sin 2A
I guess im sort of confused what is being asked, the way I attempted it was:
Assuming Sin A = $\displaystyle -sqrt(17)/9$
Then A = Arcsin( $\displaystyle -sqrt(17)/9$)
Then A = -.476
SO
(i) cos(-.476) = .889
(ii) tan(-.476) = -.515
(iii) sin(-.952) = -.814
Am I anywhere near close on this one ?, Thanks in advance for any help.
