Given the problem:

Two sides of a triangle measure 9 in. and 6 in. The measure of the inclusive angle changes from $\displaystyle 35^\circ$ to $\displaystyle 32^\circ$. Use differentials to approximate the change in the area of the triangle.

I used $\displaystyle A={\frac {1} {2}} ab \sin {C}$, where a and b are the lengths of the sides and C is the included angle, for my area function. I am just wondering if anyone has another approach for the area equation that would work well with this problem.

Thanks