How do you verify the identity (1+tantheta)/(sintheta+costheta)=sectheta?

1 Answer
Sep 11, 2016

sec theta = (1 + tan theta) / (sin theta + cos theta)

Explanation:

sec theta = 1/ cos theta

color(white)(sec theta) = 1/ cos theta * (1+tan theta)/(tan theta + 1)

color(white)(sec theta) = (1+tan theta)/(cos theta (tan theta + 1))

color(white)(sec theta) = (1+tan theta)/(cos theta (sin theta / cos theta + 1))

color(white)(sec theta) = (1 + tan theta) / (sin theta + cos theta)