## 335 Reputation

7 years, 131 days

## How do I draw this polyhedron knowing al...

Maple

How do I draw this polyhedron knowing all vertices?
https://artofproblemsolving.com/wiki/index.php/2022_AMC_10A_Problems/Problem_21?fbclid=IwAR2bdHwJEpjarZEwope1hYOcnnXqnvzae38Y8ZrfWKCKQunfAuT9s30q32o

[[-1.5, -0.5, 0.], [-1.5, 0.5, 0.], [-1., -1., -0.707107], [-1., 1., -0.707107], [-0.5, -1.5, 0.], [-0.5, -0.5, -1.41421], [-0.5, 0.5, -1.41421], [-0.5, 1.5, 0.], [0.5, -1.5, 0.], [0.5, -0.5, -1.41421], [0.5, 0.5, -1.41421], [0.5, 1.5, 0.], [1., -1., -0.707107], [1., 1., -0.707107], [1.5, -0.5, 0.], [1.5, 0.5, 0.]]

## How can I find another beautiful numbers...

Maple

The date, month, year  22/02/2022 is said a beautiful numbers. Because, the number 2202 symmetry to the number 2022. How can I find another beautiful numbers like that ?

## Are there two vectors a and b with integ...

Maple

With two vectors a and b, we know that
Norm(CrossProduct(a, b)) = Norm(a)* Norm(b) * sin(a,b).
I tried with a := <1, 2, -2>; b := <2, 10, 11>;

Note that a perpendicular to b and

Norm(CrossProduct(a, b)) = Norm(a)* Norm(b)

I tried

restart;
with(VectorCalculus);
SetCoordinates(cartesian[x, y, z]);
a := <1, 2, -2>;
b := <2, 10, 11>;
Norm(a);
Norm(b);
v := CrossProduct(a, b);
Norm(v);

Are there two vectors a and b with integer coordinates and  not perpendicular,  so that Norm(a), Norm(b), Norm(CrossProduct(a, b)) are interger numbers satisfying
Norm(CrossProduct(a, b)) = Norm(a)* Norm(b) * sin(a,b).

## How can I find three numbers a, b, c so ...

Maple

The system of equations x*y*z + y*z + y = 21, x*y*z + x*z + z = 30, x*y*z + x*y + x = 12

has three solutions, one of them is not an integer solution.

solve({x*y*z + y*z + y = 21, x*y*z + x*z + z = 30, x*y*z + x*y + x = 12}, {x, y, z})

How can I find three numbers a, b, c so that the system of equations

x*y*z + y*z + y = a, x*y*z + x*z + z = b, x*y*z + x*y + x = c

has three  solutions (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3), where x1, y1, z1, x2, y2, z2, x3, y3, z3 are nine integer numbers.

## Tetrahedron with integer volume...

Maple

Tetrahedron with length of sides like this picture has volume is an integer number. Is there another tetrahedron like that?

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