Question

Use identities to find an equivalent expression in terms of sines and cosines only.

cot θ sin θ - tan θ cos θ

Answer 1

tan theta = sin theta / cos theta

cot theta = cos theta / sin theta

cot heta * sin theta - tan theta * cos theta =

( cos theta / sin theta ) * sin theta - ( sin theta / cos theta ) * cos theta =

cos theta - sin thets

Answer 2

(cos/sin)sin - (sin/cos)cos

= cos - sin