In Exercises 1-6, (a) express dw/dt as a function of t, both by using the Chain Rule and by expressing w in terms of t and differentiating di- rectly with respect to t. Then (b) evaluate dw/dt at the given value of t. 1. w = x² + y², x = cost, y = sint; t = T 2 w = 3. w = XIN + + y², x = cost + sint, y = cost- sint; t = 0 y 2' x = cost, y = sint, z = 1/t; t = 3 4. w = In (x² + y²+z2), x = cost, y = sint, ☑ = 4√t; 1 = 3