How to simplify sine function

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Does anyone have an idea for simplifying this formula?

$$f(x)=\prod\limits_{k=2}^{14}\sin(\frac{15x\pi}{k})$$

Or even more general case:

$$f(x,y)=\prod\limits_{k=2}^{y-1}\sin(\frac{xy\pi}{k})$$

Any math trick which can help me out here?