Question

question below: (about vectors)

Answer 1

I think you just do some substitutions

Answer 2

i tried doing that but i got stuck because of the dot product..

Answer 3

Show me what you did?

Answer 4

try to imagine it graphicly:

like you should know, dot product of two vectors give a real number. This number is the length of the projection of one of the vectors onto anothers direction. So c=(b . a)a means that c and a are bouth in same direction. Or to say it other way c is (b.a) times a. This is give you some insigth on how you should continue for the proof

Answer 5

sry a is missing in the previous picture. Here it goes:

Answer 6

oh okay, i got what you mean: