Prove that the sum of all vectors drawn from the centre of a regular octagon to its vertices is the zero vector.

Define zero vector.

Prove that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Prove that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Show that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Show that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

What are the properties of a zero vector ?

Can the resultant of two vector be zero

The vector sum of a system of non-collinear forces acting on a rigid body is given to be non-zero. If the vector sum of all torques due to the system of forces about a certain point is found to be zero, does this mean that it is necessarily zero about any arbitrary point ?

Prove that the locus of a point which moves such that the sum of the square of its distances from the vertices of a triangle is constant is a circle having centre at the centroid of the triangle.

The sum of these three vectors is :