How do you simplify the expression secxcotx-cotxcosx?

1 Answer
Aug 28, 2016

secxcotx - cotxcosx=sinx for all x such that cosx, sinx != 0

Explanation:

We will use the following:

  • secx = 1/cosx
  • cotx = cosx/sinx
  • sin^2x + cos^2x = 1 => 1 - cos^2x = sin^2x

secxcotx - cotxcosx = 1/cosx*cosx/sinx - cosx/sinx*cosx

=1/sinx-cos^2x/sinx (assuming cosx != 0)

=(1-cos^2x)/sinx

=sin^2x/sinx

=sinx (assuming sinx != 0)