Question

let v=(2, 8) and w=(-1, -4) which of the following is true?
A) The x-component of v is 2
B) v and w are perpendicular
C) v*w=-34
D)v=-2w
(Check all that apply)

Answer 1

than you know that the coordinats of a point p you write in form of p=(x,y)
- so you see that for point v these coordnates are x= ? and y= ?
than how you think what is true ?

Answer 2

@graciecohen what is the dot product of those two vectors?

Answer 3

I have no idea of the answers and this is all they gave me

Answer 4

are you familiar with what a dot product is?

Answer 5

the dot product is -34 I think

Answer 6

yes thats correct

Answer 7

so assuming v*w means the dot product of v and w then you know that choice c is correct

Answer 8

looking at what @jhonyy9 wrote , can you tell if A is true or false?

Answer 9

true?

Answer 10

yep, so you know a and c are both true, lets look at b

Answer 11

if two vectors are perpendicular what does their dot product equal?

Answer 12

google it if you arent sure

Answer 13

orthogonal is perpendicular by the way

Answer 14

@graciecohen what do you think?

Answer 15

0

Answer 16

so its not perpendicular

Answer 17

correct

Answer 18

so we have a = true, b = false, c = true, what about d?

Answer 19

what is -2w equal to?

Answer 20

d is true

Answer 21

correct

Answer 22

a = true
b = false
c = true
d = true

Answer 23

thank you so much

Answer 24

yw