How does one prove sin(x+y) - sin(x-y) = 2cos(x) sin(y)?

1 Answer
AJ
Apr 16, 2018

In description

Explanation:

#sin (x+y)-sin (x-y)#
#=sinxcosy+sinycosx-(sinxcosy-sinycosx)#
#=sinxcosy+sinycosx-sinxcosy+sinycosx#
#=cancel (sinxcosy)+sinycosx-cancel (sinxcosy)+sinycosx#
#=sinycosx+sinycosx#
#=2sinycosx# henceforth proved.

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