Question

Help
Assume that u*v = 3, ||u||=7, and ||v||=3, what is the value of 5u(u-2v).

Answer 1

@ganeshie8 help

Answer 2

i got -10, but i don't think it's right

Answer 3

you want to find the dot product :-

\(5u.(u-2v)\)

Answer 4

right ?

Answer 5

right

Answer 6

dot product is distributive, so simply distribute

Answer 7

\(5u.(u-2v)\)

\(5u.u- 5u.2v\)

\(5u^2- 10u.v\)

\(5||u||^2- 10u.v\)

Answer 8

plug the given values and simplify