$w=cos(x-y),x=t^2,y=42$

$(a)$ Find $d\frac{w}{d}tby$ using the appropriate Chain Rule.

$\frac{dw}{dt}=$

$(b)$ Find $d\frac{w}{d}tby$ converting $wto$ a function $oft$ before differentiating.

$\frac{dw}{dt}=$