# Integration (Related to Physics)

1. Feb 18, 2008

### _Mayday_

[SOLVED] Integration (Related to Physics)

This shouldn't take long

I have been given the general equation for a straight line which is:

$$y=mx+c$$

Now I know that to determine the gradient I can use:

$$m=\frac{y}{x}$$

Here is my question. Can I differentiate the initial equation given to get to $$m=\frac{y}{x}$$

If so, which I am sure you can, then I seem to have come across a problem, though I think it is a problem in my differentiation.

$$y=mx=c$$

$$\frac{dy}{dx}=mx^{-1}$$

$$m=\frac{y}{x^{-1}}$$

or

$$m=\frac{x}{y}$$

This does not agree with my initial statement. Either my differentiation is incorrect or I need to touch up on my laws of indices, and if neither of these maybe I am deluded and this can't be done anyway :tongue:

_Mayday_

2. Feb 18, 2008

### Staff: Mentor

(1) The slope is given by $m = \Delta y / \Delta x$, not $m = y/x$.
(2) The derivative (with respect to x) of mx + c is just m.

3. Feb 18, 2008

### _Mayday_

Just noticed the thread title is integration not differentiation. Thank you for your help.