Question

Evaluate the expression:

v ⋅ w

Given the vectors:

r = <5, -5, -2>; v = <2, -8, -8>; w = <-2, 6, -5>
Helppppp :_(

Answer 1

well, the same as you got the dot product of the 2D vectors

Answer 2

wait what?

Answer 3

<a, b, c> \(\cdot <d, e, f> => a*d + b*e + c*f

Answer 4

<a, b, c> \(\bf\large \cdot \) <d, e, f> => a*d + b*e + c*f

Answer 5

vector v=2i-8j-8k
vector w=-2i+6j-5k
v .w =(2i-8j-8k).(-2i+6j-5k)
\[=\left( 2 \right)\left( -2 \right)+\left( -8 \right)\left( 6 \right)+\left( -8 \right)\left( -5 \right)\]
now you can calculate.

Answer 6

ahhh okay I see so -12!?

Answer 7

@surjithayer and @jdoe0001

Answer 8

you guys still there??

Answer 9

5*2*-2 => -20
-5*-8*6 => +240
-2*-8*-5 => -80
(-20) + (240) + (-80)

Answer 10

at times the system gets a bit lagged :/

Answer 11

that's alright :) and oh okay so 140? sorry before I did what @surjithayer said so I got -12?

Answer 12

But it should be 140 right?

Answer 13

yes

Answer 14

ohhh wait

Answer 15

I didn't do only u\(\cdot\) w

Answer 16

\(\bf u\cdot w will be
5*-2 = > -10
-5* 6 => -30
-2*-5 => +10

so
(-10) + (-30) + (10)

Answer 17

\(\bf u\cdot w\) will be
5*-2 = > -10
-5* 6 => -30
-2*-5 => +10

so
(-10) + (-30) + (10)

Answer 18

so -30?

Answer 19

yes

Answer 20

wait so why did we have to find 140??

Answer 21

that was a mistake I made, multiplying over too many vecors :/

Answer 22

ahh okay so v*u = -30 :)

Answer 23

thank you so much again :)

Answer 24

yw