[" 0.Prove that the sum of vectors joining the centre to all vertices of any regu "],[" is zero vector."]

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

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

Prove that the sum of the vectors represented by the sides of a closed polygon taken in order is a zero vector.

Prove that the scalar product of two or thogonal vectors is zero .

Prove that the sum of the vectors directed from the vertices to the mid-points of opposite sides of a triangle is zero.

Prove that the sum of the vectors directed from the vertices to the mid points of opposite sides of a triangle is zero

When is the sum of two non zero vectors is zero ?

By vector method prove that the straight line joining the midpoints of two non-parallel sides of a trapezium is parallel to the parllel sides and half of their sum.

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.