If F (x,y) = \frac{x^3}{y} + sinh (x) + ln (y^3) , enter the expression in x and y representing \frac{\partial^2 F}{\partial x \partial y} in the box below.
Syntax advice:
\text{Type } sqrt (x) \text{ for } \sqrt{x}, Pi \text{ for } \pi, exp(x) \text{ for } e^x, sin(x) \text{ for } sin x \text{ and } cos (x) \text{ for } cos x.
