Hello Tangera

Q1 The scalar, or dot, product of two vectors and is , where is the angle between the vectors.

Now the area of the triangle OAB

Q2 Geometrically, the dot product of and is the length of one vector multiplied by the length of the projection of the other vector onto it. So the length of the projection of onto is given by

So here we want

=

I make the answer . Would you like to have another look at it, and get back to me?

Grandad