Difference between revisions of "Q-derivative"

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(Created page with "The $q$-derivative is $$D_q\{f\}(x)=\left(\dfrac{d}{dx} \right)_q f(x) = \dfrac{f(qx)-f(x)}{qx-x}.$$ =Properties= {{:q-derivative power rule}}")
 
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The $q$-derivative is  
 
The $q$-derivative is  
$$D_q\{f\}(x)=\left(\dfrac{d}{dx} \right)_q f(x) = \dfrac{f(qx)-f(x)}{qx-x}.$$
+
$$\left(\dfrac{d}{dx} \right)_q f(x) =D_q\{f\}(x)=\left\{ \begin{array}{ll}
 +
\dfrac{f(qx)-f(x)}{qx-x} &; z \neq 0 \\
 +
f'(0) &; z=0.
 +
\end{array} \right.$$
  
 
=Properties=
 
=Properties=
 
{{:q-derivative power rule}}
 
{{:q-derivative power rule}}

Revision as of 23:56, 3 May 2015

The $q$-derivative is $$\left(\dfrac{d}{dx} \right)_q f(x) =D_q\{f\}(x)=\left\{ \begin{array}{ll} \dfrac{f(qx)-f(x)}{qx-x} &; z \neq 0 \\ f'(0) &; z=0. \end{array} \right.$$

Properties

Theorem

The following formula holds: $$D_q(z^n)=[n]_q z^{n-1},$$ where $D_q$ denotes the $q$-derivative and $[n]_q$ denotes the $q$-number.

Proof

References