Can u please explain again step by step? Its very confusing and it's on my head for almost around 2 weeks and I still haven't figured out how to solve these.Remember if the digits are odd, remove sin and and cos and vice versa, in case of tan, remove tan and add cot and vice versa.
Remember ASTC graph.
(a) sin(90 - theta) = 90 is odd so add cos remove sin. 90 - thetha = A so cos theta.
(b) sin (270+ theta) = 270 is odd so remove sin add cos, 270 + theta = C so sin is -ve = - cos theta.
(e) tan(-(180-theta)) = 180 is even, so no changes. tan(-theta) = tan theta.
REST TRY OUT YOURSELF, if u still have doubts, we are here to solve them.