# Fundamental Mathematics/Calculus/Change in variables

For any function f(x) . Over the interval of ${\displaystyle x}$ to ${\displaystyle x+\Delta x}$

Change in variable x

${\displaystyle \Delta x=(x+\Delta x)-x}$

Change in function f(x)

${\displaystyle \Delta f(x)=f(x+\Delta x)-f(x)}$