Question

Who knows how to find the equation from this graph?

Answer 1

Assume it is a quadratic. Then from the graph, you can read off the roots: call them a and b.

Then the function is
f(x) = C(x-a)(x-b)

You can then use the maximum of the function to find C.

Make sense?

Answer 2

Looks like a parabola. The vertex is at (0.6, 2800), so it's shifted .6 along x and 2800 along y. We could try to find something on the form
\[ y = c(x-0.6)^2+2800 \]
It looks like it goes through the origin, so let's choose c so this happens
\[ 0 = c(0-0.6)^2+2800 \\
c = -2800/0.6^2 \approx -7778 \]
The equation for the graph is approximately
\[ y = -7778(x-0.6)^2+2800 \]

Answer 3

That's another way to do it.

Answer 4

what dape said.

Answer 5

In general equation is given by \( (x-\alpha)^2 = 4a(y-\beta) \)

Answer 6

vertex at \(\alpha, \beta \) and 4a is the latex rectum

Answer 7

latex rectum? I'm pretty confident you could never use that term with a Western high school student.

Answer 8

Latus Rectum*

Answer 9

Even so. There's more than one way to skin this cat.

Answer 10

I agree James.

Answer 11

Do you delete my comment? :O

Answer 12

Is f(x) = C(x-a)(x-b) in "completing the square" form?

Answer 13

F= -3333t^2 + 3999.6 t
http://www.wolframalpha.com/input/?i=-3333x^2%2B3999.6x

Answer 14

but from @dape it looks like "completing the square" form, but nevermind , thanks :D

Answer 15

Do you need my working?

Answer 16

nevermind I know how to solve basic math, :D