Answer
$$\cos \left(x\right)$$
Work Step by Step
Simplifying the expression using the sum and difference formulas, we find:
$$-\cos \left(x\right)\sin \left(\frac{3\pi }{2}\right)+\cos \left(\frac{3\pi }{2}\right)\sin \left(x\right)\\ \cos \left(x\right)$$
