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# Find $a + b , 4a + 2b , \mid a \mid$, and $\mid a - b \mid$.$a = \langle 8, 1, -4 \rangle , b = \langle 5, -2, 1 \rangle$

## $$|\mathbf{a}-\mathbf{b}|=\sqrt{3^{2}+3^{2}+(-5)^{2}}=\sqrt{9+9+25}=\sqrt{43}$$

Vectors

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February 2, 2021

Is it me going nuts or does 9+9+25=45? Sgould not it equal 43?

##### Lily A.

Johns Hopkins University

##### Catherine R.

Missouri State University

##### Samuel H.

University of Nottingham

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### Video Transcript

for the given problem, we want to evaluate to some of the factors knowing that vector A is going to be 8 1 -4 And the B vector is going to be 5 -2, 1 with some of these vectors. If we do A plus B, okay, is going to be the component added together. So eight plus 5 13, 1 minus two, negative one and negative four plus one negative three. Then we want to find the magnitude of a. So magnitude of A is going to be the square root of eight squared, which is 64 Plus one Squared, which is one Um plus a negative 4th grade, which is 16. That takes us to 81 squared of 81 we know is nine. So that's the magnitude and this is the final answer.

California Baptist University

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Vectors

##### Lily A.

Johns Hopkins University

##### Catherine R.

Missouri State University

##### Samuel H.

University of Nottingham

Lectures

Join Bootcamp