.

For a) want dy/dx at t=2 and we can use dy/d/t/dx/dt= -2/10

b) at t=6, v_{x}=10, v_{y}=6 and |v|=√136

c) we have to be careful with d^{2}y/dx^{2} in parametric equations, but we can still examine

d^{2}y/dt^{2} and find at t=8 the value is negative meaning y(t) has a local maximum at t=8.

Either the maximum y is 18 at t=0 or it is at t=8

for d) the average velocity is change in position divided by change in time

and the change in position is √((change in x)^{2}+(change in y)^{2})

change in x is 120 meters,

change in y is (the integral from 0 to 12 of -t*sin(πt/4))

and change in time is 12