Question

A softball is thrown up into the air. The ball's height in feet is modeled by the equation h(t) = -16t2 + 32t + 5.
h = height
t = time in seconds
Find the maximum height of the ball.
a) 12.2 feet
b) 13.9 feet
c) 8.3 feet
d) 7.6 feet

Answer 1

find the vertex, the max height is the second coordinate of the vertex if this is for algebra
find the 1st derivative , set it equal to 0 if this is calculus, then use 1st derivative test to justify your result

Answer 2

i really dnt know how to do this

Answer 3

I am questioning those answer choices

Answer 4

plot the function in a graphing utility and you will see he answer is 21 feet, but I do not see that answer,
are you sure you copied the function correctly?

Answer 5

yes

Answer 6

\[h(t)=-16t^2+32t+5\]

Answer 7

is this for algebra or calculus class?

Answer 8

for algebra class

Answer 9

those answer choices are wrong, the answer is 21 feet

Answer 10

you can complete the square to rewrite in "vertex" form to see the vertex of the parabola or use that little formula that comes from completing square,
it would be for \[f(x)=Ax^2+Bx+C\] form the vertex is given by \[\left(\frac{B}{2A},f\left(\frac{B}{2A}\right)\right)\]

Answer 11

I agree with @ebbflo: answer is 21 feet.