Understanding Δx: The Meaning and Importance of Uppercase Delta in Math (2025)

So I'm aware that the triangle is uppercase delta which means the difference between: 10[itex]\Delta[/itex]5=5

But what does Δx mean?

MarcAlexander said:

So I'm aware that the triangle is uppercase delta which means the difference between: 10[itex]\Delta[/itex]5=5

Actually I've never seen that use of it. I'm not saying it's wrong, but it's unusual.

But in elementary math texts, [itex]\Delta[/itex]x means the amount of change in the variable x. For example, the slope of a line is [itex]\Delta[/itex]y/[itex]\Delta[/itex]x, i.e. the change in y divided by the change in x, for any two points on the line.

When you learn calculus, you will see that the instantaneous velocity of an object traveling along the x-axis is the limit of the displacement divided by the elapsed time, [itex]\Delta[/itex]x/[itex]\Delta[/itex]t, as [itex]\Delta[/itex]t approaches zero.

It's already been answered pretty good. But just to clarify:

[itex]\Delta[/itex]x = x[itex]_{2}[/itex]-x[itex]_{1}[/itex]

or the slope of a function:
[itex]\frac{\Delta y}{\Delta x}[/itex] = [itex]\frac{y_{2} -y_{1}}{x_{2}-x_{1}}[/itex]

Which you'll find to be very similar to the definition of a derivative in calculus:
[itex]\frac{\delta y}{\delta x}[/itex] which basically means (difference in y)/(difference in x)

Capital delta is looking for a specific answer (most times) while lower case is looking for another equation (most times).

Allenman said:

It's already been answered pretty good. But just to clarify:

[itex]\Delta[/itex]x = x[itex]_{2}[/itex]-x[itex]_{1}[/itex]

or the slope of a function:
[itex]\frac{\Delta y}{\Delta x}[/itex] = [itex]\frac{y_{2} -y_{1}}{x_{2}-x_{1}}[/itex]

Which you'll find to be very similar to the definition of a derivative in calculus:
[itex]\frac{\delta y}{\delta x}[/itex] which basically means (difference in y)/(difference in x)

Capital delta is looking for a specific answer (most times) while lower case is looking for another equation (most times).

What book would provide me with a quick reference to the use of greek letters in Physics?

MarcAlexander said:

What book would provide me with a quick reference to the use of greek letters in Physics?

this is helpful:
http://www.dpi.state.nc.us/docs/accountability/testing/eoc/Physics/physicsreferencetable.pdf

This has all the Greek symbols:
http://en.wikibooks.org/wiki/Physics_Study_Guide/Greek_alphabet