How do you prove (secx+tanx)(1sinx)=cosx ?

1 Answer
Feb 21, 2017

See explanation...

Explanation:

Use:

secx=1cosx

tanx=sinxcosx

cos2x+sin2x=1

Then:

(secx+tanx)(1sinx)=(1cosx+sinxcosx)(1sinx)

(secx+tanx)(1sinx)=(1+sinx)(1sinx)cosx

(secx+tanx)(1sinx)=1sin2xcosx

(secx+tanx)(1sinx)=cos2xcosx

(secx+tanx)(1sinx)=cosx