Question

find v w where v = 3i + j and w = i +3j

Answer 1

v 'cross' w ?
v 'dot' w?

Answer 2

ARE THEY COMPLEX NUMBER?
OR VECTORS?

Answer 3

i and j...
i bet vectors...

Answer 4

I agree with you DemolisionWolf

Answer 5

@scooper04 please we'd like you to reply

Answer 6

sorry
v dot x

Answer 7

v 'dot' w means you multiply the coefficients of the i componenets together and multiply the coefficients of the j components together.

v = 3i + j
w = i +3j

v 'dot' w = (3)(1)i + (1)(3)j

Answer 8

The dot product of two vectors a and b is given by \[a_{x}b_{x}+a_{y}b_{y} +...+a_{n}b_{n}\]

Answer 9

so the answer 3i + 3j

Answer 10

Yes!

Answer 11

ok what do i do with this one.
find u(vdotw) where u = 2i - j, v=3i+j and w=i+4j?

Answer 12

and you add the coefficients now.

v 'dot' w = (3)(1)i + (1)(3)j = 3+3 = 6
a dot product will return a single value. where as a cross product will return a vector

Answer 13

u=2i - j,
v=3i+j and
w=i+4j

u(vdotw)
so do the dot product for vectors V and W first..

Answer 14

so the answer for the first one is 6? not 3i +3j?

Answer 15

ya

Answer 16

when you put this:
u(vdotw)

do you mean:
u * (v 'dot' w) or
u 'dot' (v 'dot' w)?

Answer 17

u(v dot/times w)

Answer 18

here is a page:
http://mathinsight.org/dot_product_examples

Answer 19

i'm not sure what to do with the u on this new question...
I think the dot product of V and W will become a scalar that we just multiply the u vector by

Answer 20

ya, I was right in what I was thinking for the second question, just checked

Answer 21

so what does it look like im confused. im not good with this stuff and thursday is my last class.

Answer 22

first do the dot product for vector V and W because they are inside the ( )

Answer 23

that will give you a sinlgle number.
multiply that number to each term in the u vector , and ur dun

Answer 24

so (3)(4)i * (4)(3)j ?

Answer 25

u=2i - j,
v=3i+j and
w=i+4j

u(vdotw) = 2i - j (3*1 + 1*4)

Answer 26

I gotta take off, but do you see where the "3*1 + 1*4" comes from? the coefficients of the vectors V and W, take the i's times the i's coefficients, then the j's times the j's coefficients.

Answer 27

yeah i got ya

Answer 28

so it the answer 1

Answer 29

or 2
or neither

Answer 30

cool,
so then
u(vdotw) = 14i - 7j

Answer 31

sorry, open study crashed on me