A projectile is thrown upward so that its distance above the ground after t seconds is given by the function h(t) = - 16t^2 + 576t. After how many seconds does the projectile take to reach its maximum height? Show your work for full credit.

Question

jdoe0001 · Answer

take a peek at the equation => $\bf  h(t) = - 16t^2 + 576t$

what kind of graph does that look to you?

jdoe0001 · Answer

or I should write it like => $\bf  h(t) = - 16t^2 + 576t+0$

anonymous · Answer

Not sure, quadratic ?

jdoe0001 · Answer

hmm, yes but you know what... we don't have to use the quadratic for this, lemme rewrite it $\bf  h(t) = - 16t(t + 36)$

anonymous · Answer

one way is this 
|dw:1375551443353:dw|

As you can see it is half way between the zeros of the function

jdoe0001 · Answer

ohh, wait. you want to know the height.... darn ok, so, we will use the quadratic form :)

primeralph · Answer

-b/2a

anonymous · Answer

Find the roots aka zeros  and it will bee in the middle of the 2

like if its  0,5  then 3 is answer

jdoe0001 · Answer

anyhow as timo86m showed above, the leading coefficient has a negative in front of it, thus it's opening downwards, so the highest the projectile can reach, is at the vertex of the parabola

abb0t · Answer

take the derivative. set equal to zero and solve for the roots as timo said above.

anonymous · Answer

I got it guys ! Thank youu though