Question

dot product

Answer 1

Find the dot product, a • b.

a = 6i + 5j, b = -5i + 4j

Answer 2

( 6i + 5j)(-5i + 4j)

use an expansion. Just curious if "i" is just a variable, or an imaginary...

Answer 3

probably imaginary... but idk considering j is in there too .-.

Answer 4

Are you saying we have to use FOIL? I don't think it's how it works... @GABI_J

Answer 5

No, I am saying just to factor it out... I am not that dumb;)

Answer 6

factor what out?

can you be more clarification on that?

Answer 7

.-. im so confused.... so if i foil it i get 10j^2 -ji +30 right .-. or am i suppose to get i+9j?

Answer 8

trying to sound smart? Okay:)

Answer 9

I don't think you really know what dot product is.

Answer 10

.-. well if i factor it i get i+9j and you both said factor so wtf .-.

Answer 11

Just ignore GABI_J,

You simply multiply first numbers in vectors, then same thing to second numbers, then add them together.

For example:
( 1i + 2j ) • ( 3i + 4j ) = <1, 2>•<3, 4> = (1)(3) + (2)(4)
does that makes sense? @lovelyharmonics

Answer 12

.-. i dont get it

Answer 13

6i + 5j and -5i + 4j looks little messy, so let clean it a little bit:
<6, 5> and <-5, 4>

Now you just multiply first number in first vector by first number in second vector

Like this: (6)(-5)

Do same to second numbers in both vector

You should get (5)(4)

Then you add them together:

(6)(-5) + (5)(4)

does that help?

Answer 14

Basically let say you have <a,b>•<c,d>.

<a,b>•<c,d> = ac + bd

Answer 15

does that help you??

Answer 16

okay so -30 +20=10

Answer 17

*-10