Steply

u = <4, 1>, v = <1, 3>, find u - v

Step by step, with the reason for every step · Adding, subtracting, × a number · Precalculus

Step by step

The question

Question: find u − v, when u = ⟨4, 1⟩ and v = ⟨1, 3⟩.

u = ⟨4, 1⟩ and v = ⟨1, 3⟩

1 Draw tip to tail

Draw the grid.

Draw u from the origin.

Taking away v is adding −v: the arrow turned around.

Put the start of −v at the tip of u.

Tip to tail.

The answer goes from the very start to the very end.

2 Take away the parts

Take away the across parts, and the up parts.

Taking away an arrow turns it around, so its parts change sign.

u − v = ⟨4 − 1, 1 − 3⟩

4 minus 1 is 3.

1 minus 3 is −2.

So u − v = ⟨3, −2⟩.

u − v = ⟨3, −2⟩

3 Check

Let's check on the grid.

The red arrow ends at (3, −2).

That is right 3 and down 2 from the start: ⟨3, −2⟩.

The same!

tip (3, −2) → ⟨3, −2⟩

Let's look back.

First: draw tip to tail.

Then: take away the parts.

Last: check.

Answer
u − v = ⟨3, −2⟩

Your turn

Try this one yourself, then check:

u = ⟨4, 2⟩, v = ⟨3, 4⟩: find u − v
Show the answer
u − v = ⟨1, −2⟩

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