Question $1(10\%)$

Let $z=e^{uv+2},$ where $u=cos(xy)$ and $v=x^R+y^R.$

$($a$)$ Find $\frac{\text{d}\text{e}\text{l}\text{z}}{\text{d}\text{e}\text{l}\text{x}}.$

$(5$ marks$)$

$($b$)$ Find $\frac{\text{d}\text{e}\text{l}\text{z}}{\text{d}\text{e}\text{l}\text{y}}.$

$(5$ marks$)$