Pls help

1. Find the partial derivatives with respect to x and t for the function: r(x,t) = ax + bt (where a and b are constants). 2. Find the partial derivatives with respect to x and t for the function: z(x,t) = 9.8(sint) + xt +3 3. Find the partial derivatives with respect to x and y for the function: f(x,y) = xy + e* (cos y). 4. Find the partial derivatives with respect to x, y, and t for the function: f(x,y,t) = 3.2x + y-xt.