### 11.6.9 The barycenter in the plane: barycenter

See section 12.4.7 for barycenters of objects in space.

The barycenter command draws the barycenter of a set of weighted points. The points and their weights (real numbers) can be given in three different ways.

1. A sequence of lists of length two.
   The first element of each list is a point and the second element is the weight of the point.
2. A matrix with two columns.
   The first column of the matrix contains the points and the second column contains the corresponding weights.
3. A matrix with two rows and more than two columns.
   The first row contains the points and the second column the corresponding weights.

For example, the following commands will draw the barycenter of the points (1,1) with weight 1, (1,−1) with weight 1 and (1,4) with weight 2.
Input:

barycenter([1 + i,1],[1 - i,1],[1 + 4*i, 2])

or:

barycenter([[1 + i,1],[1 - i,1],[1 + 4*i, 2]])

or:

barycenter([[1 + i, 1 - i, 1 + 4*i],[1,1,2]])

Output: