Derivative of a line

Hello. In the video “Some common derivatives - Lines”, there’s an example of the derivative of a line.

I don’t understand why the coordinates for the points are such.

Hi @naticarpio98

Can you post here some screenshots?

Yes! Thank you!

The first point is
(x, y) where y=ax+b if you recall the equation of a line.
P1: (x, ax+b)

For the second point, just take a small step in x, that is \Delta x.
x x + \Delta x

Simply substitute this to the first point, then you’ll get the second point,
P2: (x + \Delta x, a(x + \Delta x)+b)

I hope it is clear.

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