How do you simplify sin(theta+pi)/cos(theta-pi)sin(θ+π)cos(θπ)?

1 Answer
Dec 7, 2016

This simplifies to tanthetatanθ.

Explanation:

Use the formulas sin(A + B) = sinAcosB + cosAsinBsin(A+B)=sinAcosB+cosAsinB and cos(A - B) = cosAcosB + sinAsinBcos(AB)=cosAcosB+sinAsinB.

=>(sinthetacospi + costhetasinpi)/(costhetacospi + sinthetasinpi)sinθcosπ+cosθsinπcosθcosπ+sinθsinπ

=>(sintheta(-1) + costheta(0))/(costheta(-1) + sin theta(0))sinθ(1)+cosθ(0)cosθ(1)+sinθ(0)

=> (-sintheta)/(-costheta)sinθcosθ

Use the identity that tanbeta = sinbeta/cosbetatanβ=sinβcosβ.

=> tanthetatanθ

Hopefully this helps!