John oflaherty2007-12-17 03:07:14

I’m trying to use muPad to plot planes to help me visualize my

calculus homework.

The plotfunc3d seems to expect an argument that expresses z in terms

of x and y.

So, for this equation of a plane, 2x – 2y + z = 12, I can rearrange it

with z as a function of x and y and plot it thus:

plotfunc3d(12-2*x+2*y)

But, x – y = 0 is a plane, parallel to z and at 45 deg. to x and y

axes. How could I get mupad to plot that?

—

john

Christopher cr2007-12-17 03:07:56

John O’Flaherty

Right, this is one way of doing it.

As a parameterized surface. Turn your plane into parametric form

(something like P(u, v) = [u, -u, v]) and plot that.

This method always works. Finding the parametric form is part of the

standard curriculum. (At least it was over here when I was in

school.) The “[u, -u, v]” above is just a short way of writing

+- -+ +- -+ +- -+

| 0 | | 1 | | 0 |

| | | | | |

| 0 | + u | -1 | + v | 0 |

| | | | | |

| 0 | | 0 | | 1 |

+- -+ +- -+ +- -+

—

+–+

+–+|

|+-|+ Christopher Creutzig (ccr@mupad.de)

+–+ Tel.: 05251-60-5525

John oflaherty2007-12-17 14:10:25

Thanks, Christopher.

—

john

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