$63-50$ Find the indicated partial derivative$($s$).$

$63.f(x,y)=x^4{y}^2-x^{2}y$;$f_{x\text{:}x,},f_{xyx}$

$64.f(x,y)=sin(2x+5y)$;$,f_{yxy}$

$65.f(x,y,z)=e^{xy{z}^2}$;$,f_{xy}=$

$66.g(r,s,t)=e^{r}sin(st)$;$,grst$

$67.W=\sqrt[\phantom{2}]{u+v^2}$;$,\frac{de{l}^{3}W}{del{u}^2\text{d}\text{e}\text{l}\text{v}}$

$68.V=ln(1+s^2+1^3)$;$,\frac{de{l}^{3}V}{\text{d}\text{e}\text{l}\text{r}\text{d}\text{e}\text{l}\text{s}\text{d}\text{e}\text{l}\text{t}}$

$69.w=\frac{x}{y+2z}$;$,\frac{de{l}^{3}w}{\text{d}\text{e}\text{l}\text{z}\text{d}\text{e}\text{l}\text{y}\text{d}\text{e}\text{l}\text{x}}*\frac{de{l}^{3}w}{del{x}^2\text{d}\text{e}\text{l}\text{y}}$