Question

u=20i+25j
use dot product to find the magnitude

Answer 1

i don't understand where the i and j go or what they are?

Answer 2

Well the dot product is used when you have TWO vectors, you only have one vector. To find the magnitude of a vector use the following formula. \[u=\sqrt{x^{2}+y^{2}} \] In where x and y are the components of the vector. @noen10 i and j are unit vectors of magnitude 1 they point towards the direction of the x and y axis respectively.

Answer 3

okay well the book only gave me one, I'm not sure how to get it from here? @Isaiah.Feynman

Answer 4

the i's and j's really mess with me. would i just solve them normally?

Answer 5

Yes just solve them normally. i and j have magnitude one, one times a number is still that number.

Answer 6

oh haha thanks, man that was messing me up.

Answer 7

@Isaiah.Feynman how do i find the magnitude of u=<3,4> and magnitude of v=<0,-2>

Answer 8

would it just be \[\sqrt{3^{2}+4^{2}}\]

Answer 9

for u?

Answer 10

Yes.

Answer 11

@Isaiah.Feynman determine if u and v are orthogonal
u=<3,15>
v=<-1,5>

Answer 12

orthogonal, neither or parallel.
i know its not orthogonal but how do i figure out if it is parallel slope?

Answer 13

Two vectors are orthogonal if they form 90 degrees with each other which means their dot product is zero.

Answer 14

Parallel slope? never heard of that.