Is there a formula for $\\sin(xy)$?

Question

Can we express a trigonometric function for the product of two angles as a function of trigonometric functions of its factors? For example: Is there a formula for $\\sin(xy)$ as a function of $\\sin x$ and $\\sin y$ or other trigonometric functions of $x$ and $y$.

Answer 1

Google "product-sum" or "product to sum" trig formulas.