Question #bf293

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Answer 1 · 2016-08-28T10:17:17

not a valid identity.

Here the left side ≠ right side as the left side equals zero, since they are 'like terms"

#rArrcos(x+y)-cos(x+y)=0#

Answer 2 · 2016-08-28T22:51:04

The left side is 0.

Let's say cos(x=y) represents x. When we plug x in, x-x definitely =0.