Hi:

Try this:

plot(c(0, 1), c(0, 1))
text(0.5, 0.5, expression(x == over(-b %+-% sqrt(b^2 - 4 * a * c), 2 * a)))

I've found it useful to print out the different plotmath expressions:

pdf('plotmath.pdf')
demo(plotmath)
dev.off()

HTH,
Dennis


On Thu, Jan 21, 2010 at 2:10 PM, Jason Rupert <jasonkrupert@yahoo.com>wrote:

> Is there a way to display something like the quadratic equation, i.e. with
> a numerator and demonator on a plot?
>
> I think there is a way to create the equation in Latex, but wasn't sure if
> this format would translate to plotting.
>
> \begin{equation}
>   x = \frac{b +/- sqrt(b^2 - 4*a*c)}{2*a}
> \end{equation}
>
>
> My searched turned up the following:
> http://tolstoy.newcastle.edu.au/R/e6/help/09/03/9010.html
>
> Unfortunately, it does not address equations with numerators and
> demomenators.
>
> Here is a guess (but this fails):
>
> ### Change spacing to allow for multiline title
> par(oma=c(2, 0, 4, 0))
> ### Some greek letters
> mu <- 0
> alpha <- 1
> beta <- 2
> delta <- 3
> lambda <- 4
> ### Some graph or other
> plot(1:10,1:10)
> mtext(expression(bold("Meaningless Title")),
>       line=3.5,cex=1.15)
> mtext(bquote(x == \frac{b +/- sqrt(b^2 - 4*a*c)}{2*a}, line=2.25,cex=1.15)
>
>
> Thanks again for any and all help.
>
>
>
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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