Let $f(x, y)=y^{2}+3 y \int_{3}^{x} \sin \left(e^{t}\right) d t$ Find $f _ { x } ( 3,1 )$

Essay

Let $f(x, y)=y^{2}+3 y \int_{3}^{x} \sin \left(e^{t}\right) d t$ Find $f _ { x } ( 3,1 )$ and $f _ { y } ( 3,1 )$ to four decimal places.