# Math Help - How can you differentiate sinx.cosy.cosz?

1. ## How can you differentiate sinx.cosy.cosz?

What method is used?

Can the product rule be extended for a third dimension.

I know that for cosx.siny you can use dy/dx=u*(dv/dx) + v*(du/dx)

But what can be used to differentiate sinx.cosy.cosz? can the above rule be extended for a third dimension?