How do you verify sinx + cosx + tanxsinx = secx + cos x tan x?

1 Answer
Jul 9, 2016

Apply the identities sectheta = 1/costheta and tantheta = sintheta/costheta.

sinx + cosx + sinx/cosx xx sinx = 1/cosx + sinx/cosx xx cosx

Put on a common denominator:

(sinxcosx + cos^2x + sin^2x)/cosx = (1 + sinx cosx)/cosx

Recall that sin^2beta + cos^2beta = 1:

(1 + sinx cosx)/cosx = (1 + sinx cosx)/cosx

Hopefully this helps!