5. Assume x = x(t), y = y(t) and z = z(t) and that x2 + y2 + z2 = 100, find dz/dt if x = 6, y = 7, dx/dt = 2 and dy/dt = -5 R The volume of a cone is V = (1/3) TI R2h, 6. Suppose the height of a cone h is always 3 times of R and its volume V expands from V = 1000 TT m3 to (1000 TT + 1) m3, approximate the change in radius with dr. 7. Suppose that R and h are changing that R is increasing at a rate of 2 m/sec and h is decreasing at 4 m/sec, find rate of change in volume when R = 10 m and h = 20 m. 8 Select a function y = f(x), x and dx and find dy to approximate (1001) 1/3