Question #40916

2 Answers
Oct 29, 2017

Proof via considering trig identities

Explanation:

First we consier #1-2sin^2x# as being #cos^2x-sin^2x#
As; #1-2sin^2x# = # (1- sin^2x) -sin^2x#
and #1-sin^2x# = #cos^2x#

So we can simplify the LHS to #(cos^2x-sin^2x)/(cosx+sinx)#

Hence #cos^2x-sin^2x# can be written as #(cosx+sinx)(cosx-sinx)# by difference in two squares

Hence we can simplify the LHS to # ((cosx+sinx)(cosx-sinx))/(cosx+sinx)#

Hence cancelling, to yields, #cosx-sinx#

#LHS = RHS#

Oct 29, 2017

See other answer.

Explanation:

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