(Solved): Verify that the equation is an identity. \[ \cos (x+y)+\cos (x-y)=2 \cos x \cos y \] \[ \cos (x+y)+ ...

Verify that the equation is an identity. \[ \cos (x+y)+\cos (x-y)=2 \cos x \cos y \] \[ \cos (x+y)+\cos (x-y) \] \[ =1+1 \] (Type the terms of your expression in the same order as they appear in the onginal expression.) Verify that the equation is an identity. \[ \cos (x+y)+\cos (x-y)=2 \cos x \cos y \] \[ \cos (x+y)+\cos (x-y) \] \[ =1+1 \] (Type the terms of your expression in the same order as they appea Use the sum and difference identities Use the quotient identities. Use the even-odd identities: Use the Pythagorean identities.