Reduce to one trig identity. sec(x)+sin(x)tan(-x)=? I know it equals cos(x) but how?

1 Answer
Oct 15, 2017

secx+sinxtan(-x)=cosxsecx+sinxtan(x)=cosx

Explanation:

We shall use the following identities:

tan-=sin/costansincos

tan(-x)=-tanxtan(x)=tanx

secx=1/cosxsecx=1cosx

"Prove that "secx+sinxtan(-x)=cosxProve that secx+sinxtan(x)=cosx

secx+sinxtan(-x)=1/cosx-sinxsinx/cosx=(1-sin^2x)/cosx=cos^2x/cosx=cosx " as required, "OEDelta