Homework 3. A large snowball is melting according to the (b) the instantaneous rate of change at t-9 equation ptr)-144-r2. find: the average rate of change between t . 4 and (a) 9 4. Find the gradient of the tangent of a)t(x) = 7x'-8x2 + 3x + 2 atx=-1 b) f(x)-5- atx=2 x 6. Find the average rate of change For ). find the rate of change on the interval [-2, 4]. of f(x)=x2+x over the interval [1,3]