Question

Find a ⋅ b.

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

-4

<8, 1>

<16, -20>

-36

Answer 1

@SolomonZelman
@tkhunny

Answer 2

You are calculating the inner product. You should get a scalar. Let's see it!

Answer 3

ok,thnx for replying:)

Answer 4

what do i do now?

Answer 5

Question: Why do you have an inner product question without ever seeing it done?

Answer 6

i saw it done but i still didn't get it.

Answer 7

@chantz417

Answer 8

cn u help me?

Answer 9

im not quite sure on this one sorry

Answer 10

that's fine:)

Answer 11

Okay, use the Inner Product Formula.

\(<e,f>\cdot<c,d> = e\cdot c + f\cdot d\)

You have a = 4i - 4j, b = 4i + 5j

\(<4,-4>\cdot<4,5> = 4\cdot 4 + (-4)\cdot 5 = 16 - 20 = -4\)

That's about it. You do some. Let's see what you get.

Answer 12

thnx alot @tkhunny :)

Answer 13

No samples from you?

Answer 14

what do u mean?

Answer 15

Show me this one:

a = 4i - 3j, b = 2i - 2j

What is \(a\cdot b\)

Answer 16

<4,-3><2,-2>
<8,6>

Answer 17

<8,6> is no good. It's still a vector. You should get the scalar 8+6 = 14.

Good work. Pretty close.

Answer 18

ok,and what does a scalar exactly mean?

Answer 19

It's a number with no units or any other encumbrance.

14 lbs -- Not a scalar.
<3,4> - Not a scalar.
{1, 3, 6} -- Not a scalar.
12 -- Scalar

Answer 20

thnxagain.wuld u mind helping me on another question?

Answer 21

Please post on a new thread. Show your work!

Answer 22

ok.