Engineering Handbook/Calculus/Change Variable

Change Variable

Let x be the integer variable then the change in variable x can be defined as

$x-x_{o}=\Delta x$

Therefore

$x=x_{o}+\Delta x$

if there is a function of x f(x) then a change in variable x causes a change in the function as

$\Delta f(x)=f(x)-f(x_{o})$

Then

$f(x)=f(x_{o})+\Delta f(x)$