How do you simplify the expression secxcotxcotxcosx?

1 Answer
Aug 28, 2016

secxcotxcotxcosx=sinx for all x such that cosx,sinx0

Explanation:

We will use the following:

  • secx=1cosx
  • cotx=cosxsinx
  • sin2x+cos2x=11cos2x=sin2x

secxcotxcotxcosx=1cosxcosxsinxcosxsinxcosx

=1sinxcos2xsinx (assuming cosx0)

=1cos2xsinx

=sin2xsinx

=sinx (assuming sinx0)