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 Message Boards » » Finding the function equation of a graph Page [1]  
ModestMouse
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I've been given a graph with a z-shaped piecewise function on it, I know y=f(x).

I'm supposed to find f(1) and the equations of the piecewise functions, but I can't get it right in my head. Any help?

4/29/2007 7:40:17 PM

LimpyNuts
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post a picture of the graph.

4/29/2007 9:20:25 PM

humandrive
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f(x)= x

4/29/2007 9:45:58 PM

Excoriator
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you have to do a curve-fit on it if it is curved. if you don't know how to do a curve-fit and the graph has a curve, then go study for one of your other classes; you'll be failing this one anyway.

if it is composed of straight lines then its relatively easy.

y = f(x) = mx + b; x1 =< x =< x2

where x1 and x2 are the starting and ending x coordinates of each straight line segment respectively

take each straight-line segment and draw a dashed line continuing the segment left and right. wherever the dashed line intersects the Y axis is "b" in the equation above. if you don't know how to figure out "m" then, again, study for another class; you'll be failing this one


In the end you should have something that looks like this:

y = f1(x) = m1x + b1; x1 =< x =< x2
= f2(x) = m2x + b2; x3 =< x =< x4
= f3(x) = m3x + b3; x5 =< x =< x6

[Edited on April 29, 2007 at 10:05 PM. Reason : s]

[Edited on April 29, 2007 at 10:06 PM. Reason : s]

[Edited on April 29, 2007 at 10:08 PM. Reason : s]

4/29/2007 10:04:52 PM

FykalJpn
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Quote :
"post a picture of the graph."

4/30/2007 2:06:30 PM

soulfire963
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i bet its a variation of y = 1/x if it has an asymptote in the middle that is, but in some cases it looks like a Z

4/30/2007 6:23:29 PM

mathman
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its a trick, z doesn't pass the vertical line test. It can't be the graph y=f(x).

[Edited on April 30, 2007 at 8:22 PM. Reason : motives.]

4/30/2007 8:22:19 PM

Excoriator
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f(x) could be piecewise

[Edited on May 2, 2007 at 12:17 PM. Reason : s]

5/2/2007 12:17:15 PM

 Message Boards » Study Hall » Finding the function equation of a graph Page [1]  
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