Which of the following is an identity?

W) \(\cos(2x)=2\)\(\cos(x)\)[cosine of 2x equals 2 cosine of x]

X) \(\sin(2x)=2\)\(\sin(x)\)\(\cos(x)\)[sine of 2 x equals 2 sine of x cosine of x]

Y) \(\cos(x+y)=\cos(x)+\cos(y)\)[cosine of the quantity x plus y equals cosine of x plus cosine of y]

Z) \(\sin(x\) - \(y)=\sin(x)\) - \(\sin(y)\)[sine of the quantity x minus y equals sine of x minus sine of y]
X) \(\sin(2x)=2\)\(\sin(x)\)\(\cos(x)\)