Question

sinx+siny=a
cosx+cosy=b
cos(x+y) =b^2-a^2/a^2+b^2

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Answer 1

Step-by-step explanation:

sinx+siny=a and cosx+cosy=b, then cos(x-y) is equal to 1,2(a^2+b^2-2 )(B)1,2(a^2+b^2+2)