Question #1415a

1 Answer
Narad T.
Nov 24, 2017

See the proof below

Explanation:

You need

#tanx=sinx/cosx#

#cotx=cosx/sinx#

We start on the right hand side

#RHS=(tanx-1)(cotx+1)#

#=tanx*cotx+tanx-cotx-1#

But

#tanx*cotx=sinx/cosx*cosx/sinx=1#

Therefore,

#RHS=1+tanx-cotx-1=tanx-cotx#

#=LHS#

#QED#

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