How to draw a triangle...

[-MFra-]

Hello everyone,

Someone knows a smarter way to draw an equilateral triangle?

Thank you very much.

[LucMeekes]

Success!

Luc

[-MFra-]

Oh! yes nice,

but my version considers the height of the triangle, changing which, for example, I get an isosceles triangle. however, the use of other geometric figures to build the triangle is not welcome.

[LucMeekes]

The general case, for an n-angle and orientation o, is:

Success!
Luc

[Werner_E]

Not sure what exactly you are looking for.

If your goal is to just draw an equilateral triangle dependent on the side length and in the same position in the coordinate system as yours, a simple way would be this:

As Luc wrote, three points are all you need - actually four as you have to duplicate the first one to get a closed figure. You can leave it to Mathcad's 2D plot to connect the points.

[Werner_E]

Just read your answer to Luc's post where you say that you also want to draw isosceles triangles depending on the base length and the height.

Here it is:

[-MFra-]

Undoubtedly, I have unclearly posed my question. The fact is that the sides of the triangle are the contour of a hollow metal structure. Within it, there is a physical quantity, solution of a pde, which must vanish on them, so it is not possible to use the matrix, because I can't apply the boundary conditions, even if your solution is very cool.

[Werner_E · Accepted solution]

OK, so the goal is not (or not only) drawing, but rather ....??

Do you need a function of some kind which also gives you any point on the sides of the triangle, not just the vertices? Or is Luc's approach already doing what you have in mind?

[-MFra-]

yes, that's right, I have to find a function that vanishes on all inner sides of the triangle and satisfies the Helmholtz equation. I think it is beyond your task.

[Werner_E]

At least here's a parametrized function for the border

And in case Valery is watching ....

And here a very short parametric representation, using absolute values instead of if-statements:

MC15 file attached