Question re: difference between Δx and dx

[yoshtov]

Homework Equations

dL = L₀αdT

ΔL = L₀αΔT

These two equations are both listed separately on my equation sheet. How are the dL and ΔL terms different?

 

[QuarkCharmer]

I think that Δx could just indicate a change in something. In physics for example,
Δx = x2 - x1

dx however, indicates the infinitesimal change in x.

 

[256bits]

Take for instance a curved line.
You want to find the slope m of the curve at point (x,y).

There are a few procedures such as the tangential rule or the secant rule.

But simplictically, assume x is midway between 2 points x1 and x2, and y is midway between corrsponding points y1 and y2.
Then m = (y2-y1)/(x2-x1)
Or, m= Δy / Δx ( if y2-y1 and x2-x1 are not too great )

As Δx or Δy is made to become smaller and smaller to the limit of approaching 0(zero)
Then m=dx/dy