I need help with one problem. Automatic Medal and Fan if you help meee!!!!!

Question

rocketisawesome · Answer

A ball is thrown vertically upward. After t seconds its height h (in feet) is given by the function h(t)=68t-16t^2. What is the maximum height that the ball will reach? Do not round your Answer.

anonymous · Answer

http://www.algebra.com/algebra/homework/word/mixtures/Mixture_Word_Problems.faq.question.359046.html

anonymous · Answer

the answer is on that website

rocketisawesome · Answer

look it is a different question

rocketisawesome · Answer

@alibaby

phi · Answer

put your equation into standard form (for a parabola)
$$  h(t)=-16t^2 +68t + 0$$
(we normally don't show the +0 )
now match that up with
ax^2 + bx +c
and use the formula for the vertex (the peak of the parabola)
which is at x= -b/(2a)

or in this case, at t=  fill in the numbers for a and b)

rocketisawesome · Answer

oh

phi · Answer

once you find t, you can use it in the formula to find the actual height

phi · Answer

what do you get for t?

rocketisawesome · Answer

How exactly would I get t?

phi · Answer

first look at your equation
$$ h(t)=-16t^2 +68t + 0 $$
which number corresponds to "a"  ? any idea  ?

phi · Answer

The idea is "a" stands for the coefficient on the "highest order term"
i.e. the t^2 term

rocketisawesome · Answer

no idea

phi · Answer

in other words, what is the number in front of the $t^2$?

rocketisawesome · Answer

16

phi · Answer

almost

rocketisawesome · Answer

-16

phi · Answer

yes

and to "talk about" that number we call it "a"
and we call the number in front of the $ t$ term (the 2nd term) "b"
what is b?

rocketisawesome · Answer

68?

phi · Answer

yes.

and the formula for the vertex of the $ \cap$ is
$$ t= \frac{-b}{2a}$$
we replace b with the number we found
and we replace the a with the number you found for a
can you do that ?

rocketisawesome · Answer

so $$\frac{ 16 }{ 136 }$$

rocketisawesome · Answer

?

rocketisawesome · Answer

@phi

phi · Answer

b is 68
-b means put a minus sign (multiply by -1) in front of b: 
so -b is -68

-68  goes in as the "top" in
-b/(2a)

in other words  we have (so far)
-68/(2a)

now you try the bottom:  you want to put in 2 times a as the bottom

rocketisawesome · Answer

that's what I did $$\frac{ 16 }{ 136 }$$

rocketisawesome · Answer

-16/136

phi · Answer

can you do 2 * a 
(remember a is -16)

phi · Answer

you switched a and b.  right idea, but wrong numbers