# Drawing a Convex Hull in Maple

1. Jun 8, 2007

### Mathman23

Urgent Question: Drawing a Convex Hull in Maple

1. The problem statement, all variables and given/known data

Drawing a Convex Hull of 5 2D Points....

2. Relevant equations

None

3. The attempt at a solution

Hi there,

I am trying draw the convex hull of the 5 points x1,x2,x3,x4,x5 below.

Is this the correct way of doing this??

The points are presented in the nation $$x_i = (a,b)^t$$.

What eactly does this mean?

I know that $$A^t$$ means a transposed matrix.

Does $$x_i = (a,b)^t$$ simply mean $$x_i = \left[\begin{array}{c} a \\ b \end{array}\right]$$ ??
Do I need to make the maple sheet below not draw the complete complex hull?

Code (Text):
with(geometry);
[Apollonius, AreCollinear, AreConcurrent, AreConcyclic,

AreConjugate, AreHarmonic, AreOrthogonal, AreParallel,

ArePerpendicular, AreSimilar, AreTangent, CircleOfSimilitude,

CrossProduct, CrossRatio, DefinedAs, Equation, EulerCircle,

EulerLine, ExteriorAngle, ExternalBisector, FindAngle,

GergonnePoint, GlideReflection, HorizontalCoord,

HorizontalName, InteriorAngle, IsEquilateral, IsOnCircle,

IsOnLine, IsRightTriangle, MajorAxis, MakeSquare, MinorAxis,

NagelPoint, OnSegment, ParallelLine, PedalTriangle,

SensedMagnitude, SimsonLine, SpiralRotation,

StretchReflection, StretchRotation, TangentLine,

VerticalCoord, VerticalName, altitude, apothem, area,

asymptotes, bisector, center, centroid, circle, circumcircle,

conic, convexhull, coordinates, detail, diagonal, diameter,

dilatation, directrix, distance, draw, dsegment, ellipse,

excircle, expansion, foci, focus, form, homology, homothety,

hyperbola, incircle, inradius, intersection, inversion, line,

medial, median, method, midpoint, orthocenter, parabola,

perimeter, point, powerpc, projection, radius, randpoint,

reciprocation, reflection, rotation, segment, sides,

similitude, slope, square, stretch, tangentpc, translation,

triangle, vertex, vertices]

> point(x1,[-1,-1]),point(x2,[-1,1]),point(x3,[0,-1]),point(x4,[2,0]),point(x5,[1,1]): hullname:=convexhull({ x1, x2, x3, x4, x5});

> Polygen(hullname): draw({x1,x2,x3,x4,x5},printtext=true,axes=NONE);

Here is a printout of the Convex Hull:

Do this look okay??

Secondly I have tried to draw the polygon in maple, but I am unable to complete the convex hull, and label the vertices.

Here is the code that I used, maybe there is somebody who can gave me a hint on howto label the vertices, and to plot the convex hull ?

Code (Text):
with(plottools):
> l := polygon([[-1,-1], [-1,1], [0,-1],[2,0],[1,1]], color=black, linestyle=3, thickness=2);
> plots[display](l);
Best Regards
Fred

Last edited: Jun 8, 2007