Steply

u = <2, 3>, v = <4, -1>, 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 = ⟨2, 3⟩ and v = ⟨4, −1⟩.

u = ⟨2, 3⟩ and v = ⟨4, −1⟩

1 Draw tip to tail

Draw the grid.

Draw u from the origin.

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 Add the parts

Add the across parts, and the up parts.

Each arrow adds its own across and up.

u + v = ⟨2 + 4, 3 + (−1)⟩

Adding a negative is the same as taking away.

+ (−) = −

2 plus 4 is 6.

3 plus (−1) is 2.

So u + v = ⟨6, 2⟩.

u + v = ⟨6, 2⟩

3 Check

Let's check on the grid.

The red arrow ends at (6, 2).

That is right 6 and up 2 from the start: ⟨6, 2⟩.

The same!

tip (6, 2) → ⟨6, 2⟩

Let's look back.

First: draw tip to tail.

Then: add the parts.

Last: check.

Answer
u + v = ⟨6, 2⟩

Your turn

Try this one yourself, then check:

u = ⟨4, 5⟩, v = ⟨1, −1⟩: find u + v
Show the answer
u + v = ⟨5, 4⟩

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