how dy/dx and y2-y1=m(x2-x1) related?

**ameerulislam** · December 15th 2012, 09:20 PM

how dy/dx and y1-y2=m(x2-x1) related?

I mean shouldn't dy/dx = m ?

**MarkFL** · December 15th 2012, 09:32 PM

The tangent line to a differentiable function at the point $(x_1,y_1)$ is:

$y-y_1=f'(x_1)(x-x_1)$

**Prove It** · December 15th 2012, 09:35 PM

Originally Posted by ameerulislam

how dy/dx and y1-y2=m(x2-x1) related?

I mean shouldn't dy/dx = m ?

dy/dx is a FUNCTION which tells you what the gradient of your function y is at any point.

m is the gradient of your tangent line at a SINGLE point.

**ameerulislam** · December 15th 2012, 10:06 PM

Originally Posted by Prove It

dy/dx is a FUNCTION which tells you what the gradient of your function y is at any point.

m is the gradient of your tangent line at a SINGLE point.

If you can please provide an example that would be great! I'm like getting it and not getting it.. tx

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