# Math Help - max velocity

1. ## max velocity

how do you find the maximum velocity of

s(t)=-93.75t^3+93.75t^2+45t

step by step to the answer would help a ton..

2. Originally Posted by unknown2221
how do you find the maximum velocity of

s(t)=-93.75t^3+93.75t^2+45t

step by step to the answer would help a ton..
s'(t) = 3*(-93.75)t^2 + 2*93.75t^2 +45

s'(t) = 0

can you solve it?

...

$s_1 = \sqrt{61} /15 + 1/3$

$s_2 = -\sqrt{61} /15 + 1/3$

f''(s) = ??

f''(s_1) < 0 => maximum

f''(s_2) > 0 => minimum

3. Don't post the same question twice. It wastes everyone's time. I already answered your question here: http://www.mathhelpforum.com/math-he...tml#post227406