What does this mean?

[noregret]

What does it mean by the rate of the change of the dependent variable with respect to the independent variable?

[MightyBeh]

99% sure it's just the same thing as normal - dependant variable is usually the vertical axis (it's dependant on the horizontal, like distance travelled) and the independent is the horizontal axis (because it can exist without the dependent variable, like time). So it's the derivative dy/dx, but it's actually dDV/dIV.

[fred42]

The independent variable, usually x, is whatever the horizontal axis is labelled and the dependent variable, usually y, is whatever the vertical axis is labelled. Examples are dy/dx, dV/dt, dA/dt etc.