Question

Landon is standing in a hole that is 5.1 ft deep. He throws a rock, and it goes up into the air, out of the hole, and then lands on the ground above. The path of the rock can be modeled by the equation y = -0.005x2 + 0.41x - 5.1, where x is the horizontal distance of the rock, in feet, from Landon and y is the height, in feet, of the rock above the ground. How far horizontally from Landon will the rock land?

Answer 1

when y=0, we are on the ground

Answer 2

using the quadratic formula will greatly simplify this process

Answer 3

your option is to determine when y=0 since that is when the rock hits the ground and stops moving

Answer 4

i donno how to do this crap lol ...

Answer 5

the quadratic formula is simple enough; its just a matter of plugging in the values we see in the original equation to determine x

Answer 6

might be simple to u, but im not good at math, on top of that been like 6 years plus since ive done any of this

Answer 7

given the equation: y = ax^2 + bx + c , we can determine the value of x such that y=o when:\[x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}\]

Answer 8

it was 20 years before i went to college and had to recall all this stuff :)

Answer 9

thats awesome u member this. wish my brain worked that way with math, im like that with other stuff jus not this

Answer 10

i just need the answer to it lol

Answer 11

following the formula we are given that

-0.005x2 + 0.41x - 5.1

a = -.005
b = .41
c = -5.1

(-.41 + sqrt((.41)^2-4(-.005)(-5.1)))/(2(-.005))

hopefully i wrote that up right, lets see what the google calculator gives us

http://www.google.com/search?sugexp=chrome,mod=8&sourceid=chrome&ie=UTF-8&q=(-.41+%2B+sqrt((.41)%5E2-4(-.005)(-5.1)))%2F(2(-.005))

that says we get a value of about 15, we also get a value of about 66 which we can prolly ignore

Answer 12

this inst really spose to be a "give out the answer only" kind of website.

this is a study site meant to facilitate learning the stuff

Answer 13

well kind of hard to learn over the internet considering i prolly would have learned it from books an havnt lol

Answer 14

answers can be gotten from sites like:

http://www.wolframalpha.com/input/?i=+-0.005x2+%2B+0.41x+-+5.1

which tells me that the farther distance is correct