Question

What is the slope of a horizontal line?

Answer 1

try taking any 2 points on any horizontal line, and plugging them into the slope formula.

(the y-values will always be the same)

Answer 2

dy/dx = (y2-y1)/(x2-x1) etc.

Answer 3

why are you differentiating?

Answer 4

the slope is the change in y divided by the change in x, the tangent, the differential, etc.
If I wrote the equation with an editor, dy would have been capital delta y....

Answer 5

I know, but jr221 hasn't learned this yet.

Answer 6

Yes, the point was the right-hand-side of the equation, not the "dy/dx."

Answer 7

But I agree that "dy/dx" was a poor choice.