Skateboarders Velocity is given as

Question

v=3t-0.2t^2

What is his max velocity

Answer 1

To get the max velocity, first, differentiate the velocity equation with respect to time. Then equate to zero:
dv/dt = 3 - 0.4t
0 = 3 - 0.4t
0.4t = 3
t = 7.5
Substitute to the original equation:
v = 3t-0.2t^2
v = 3(7.5) - 0.2(7.5)^2
v = ?

Or you may also want to plot the equation. You should get a parabola which has a maximum. That max point corresponds to the velocity (y-coordinate) at a particular time (x-coordinate).

Hope this helps~ :)

Answer 2

THANKS MATE !