Asked by mien

in proving trigonometric identities if sec theta - tan theta sin theta is equal to cos theta. what is the correct answer?
Answered by Reiny
secØ - tanØsinØ = cosØ

LS (left side)
= 1/cosØ - (sinØ/cosØ)sinØ
= (1 - sin^2 Ø)/cosØ
= cos^2 Ø/cosØ
= cosØ
= RS