Plotting piecewise parametric function

1. Apr 23, 2010

fishingspree2

I want to plot on the same graph:

1 < t < 2
x(t) =1.146967180*(t-1)^3-2.178399723*(2-t)^3+38.3612214*t+106.1461765
y(t)=.3047483217*(t-1)^3-.5750322227*(2-t)^3+10.1163822*t+444.0230985

2 < t < 3
x(t)=-.4672626810*(t-2)^3+1.146967180*(3-t)^3+45.2430246*t+92.3825701
y(t)=-.1402738345*(t-2)^3+.3047483217*(3-t)^3+11.9448719*t+440.3661194

What software allows me to plot this, a parametric piecewise curve?

Thank you very much

2. Apr 23, 2010

hotvette

Depends on how fancy you want the plot to look. It would be pretty easy to do in Excel.

3. Apr 23, 2010

fishingspree2

It isn't possible with gnuplot, maple, octave or mathematica? I can't believe such a simple thing is not possible :S

How to do it with excel?

4. Apr 23, 2010

hotvette

If your value of t is in cell A1, the following for x goes in B1:

Code (Text):
=IF(A1>2,-0.467262681*(A1-2)^3+1.14696718*(3-A1)^3+45.2430246*A1+92.3825701,1.14696718*(A1-1)^3-2.178399723*(2-A1)^3+38.3612214*A1+106.1461765)
and the following in cell C1 for y:

Code (Text):
=IF(A1>2,-0.1402738345*(A1-2)^3+0.3047483217*(3-A1)^3+11.9448719*A1+440.3661194,0.3047483217*(A1-1)^3-0.5750322227*(2-A1)^3+10.1163822*A1+444.0230985)
Took about 2 minutes. Plot isn't very inteststing - very linear. Log-log version has a slight curve to it. The other programs I (unfortunately) don't know at all.

5. Apr 23, 2010

Hepth

In Mathematica:

Show[ParametricPlot[{1.146967180*(t - 1)^3 - 2.178399723*(2 - t)^3 +
38.3612214*t + 106.1461765,
0.3047483217*(t - 1)^3 - .5750322227*(2 - t)^3 + 10.1163822*t +
444.0230985}, {t, 1, 2}, PlotRange -> {{140, 200}, {440, 500}}],
ParametricPlot[{-0.4672626810*(t - 2)^3 + 1.146967180*(3 - t)^3 +
45.2430246*t +
92.3825701, -0.1402738345*(t - 2)^3 + .3047483217*(3 - t)^3 +
11.9448719*t + 440.3661194}, {t, 2, 3},
PlotRange -> {{140, 300}, {440, 500}}]]

6. Apr 23, 2010

fishingspree2

Hello, where did you get the PlotRange values? Are they really needed?