Question

what is the value of cotx-sin(pi/2-x)cos(pi/2-x)
(i)cotx cos^2x
(ii)cot^2x
(iii)cos^2 x
(iv)tan^2x

Answer 1

\[\large{\sin (\cfrac{\pi}{2} - x) = \cos x}\]

\[\large{\cos (\cfrac{\pi}{2} - x) = \sin x}\]

Using this can you simplify the LHS ?

Answer 2

is that a identity

Answer 3

or how can we prove it

Answer 4

Actually the (pi/2 - x) things are no such identities ..... but it is useful to remember them.