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Prove that:cos(pi/4-x)cos(pi/4-y)-sin(pi...

Prove that:`cos(pi/4-x)cos(pi/4-y)-sin(pi/4-x)sin(pi/4-y)=sin(x+y)`

Text Solution

Verified by Experts

LHS. `=cos(pi/4-x) cos(pi/4-y)-sin(pi/4-x)sin(pi/4-y)`
`=cos[pi/2-(x+y)]`
`=sin(x+y)`= RHS Hence Proved.
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