       Re: Mathematica (plotting a point on a graph)

• To: mathgroup at smc.vnet.net
• Subject: [mg26016] Re: Mathematica (plotting a point on a graph)
• From: dkeith at sarif.com
• Date: Thu, 16 Nov 2000 03:43:03 -0500 (EST)
• References: <8ur0p8\$quo@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Narash,

Here is one way. Define a function Mathematica style, solve the second
derivative==0 and get the coordinates of the inflection point, then
plot the function with the point plotted as a graphics primitive using
the Epilog option to Plot.

Regards,

David

f[x_] := 2x^3 - 3x^2 - 12x

xInflection = y /. Solve[D[f[y], {y, 2}] == 0][]

yInflection = f[xInflection]

Plot[f[x], {x, -5, 5},
Epilog -> {PointSize[.02], Point[{xInflection, yInflection}]}]

In article <8ur0p8\$quo at smc.vnet.net>,
"Narésh R Ganta" <nganta82 at hotmail.com> wrote:
> I went to you Mathematica website, and I have a question. Here is my
> problem. If I have F(x)=2x^3-3x^2-12x and I found that the inflection
point
> to be (.5,-6.5), how can I plot F(x), and show the inflection point
on the
> same graph?
>
> Thanks
>

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