help with vectors and dot products

[piratefan5247]

||u||=2
||v||=3
||w||=5
u dot v = -1
u dot w = 1
v dot w = -4

Compute:
a. ||-4w||
b. (u+w) dot v
c. ||u+v||^2
d. ||v-4w||^2

I have no idea how to do any of these... we went over dot products with a matrix... but I'm not sure how to do this..

 

[Deleted member 4993]

||u||=2
||v||=3
||w||=5
u dot v = -1
u dot w = 1
v dot w = -4

Compute:
a. ||-4w||
b. (u+w) dot v
c. ||u+v||^2
d. ||v-4w||^2

I have no idea how to do any of these... we went over dot products with a matrix... but I'm not sure how to do this..

What does your text book say?

Do you see that

||u+v||^2

= (u + v) . (u + v)

Can you expand the expression above (treating u and v as vectors)?

Show us some work - so that we know where to begin to help you.