How do you prove: #Cosx + sinx tanx = secx#?

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Answer 1 · 2018-03-04T05:03:03

See below.

We have:

#LHS=cosx+sinxtanx# and #RHS=secx#

We change the #LHS#:

#cosx+sinx*sinx/cosx#

#= cosx+sin^2x/cosx#

#= (sin^2x+cos^2x)/cosx#

#= 1/cosx#

#= secx#

So #LHS=RHS#

Hence, proved.