Question

show that cosx(270degree +theta)/cos(360degree - theta)= tantheta

Answer 1

cos(270^o+θ)/cos(360^o-θ)=(cos(270^o)cos(θ)-sin(270^o)sin(θ))/(cos(360^o)cos(θ)+sin(360^o)sin(θ))=(0*cos(θ)-(-1)*sin(θ))/(1*cos(θ)+0*sin(θ))=sin(θ)/cos(θ)=tan(θ)

Q.E.D.