Difference between revisions of "Delta derivative of quotient"

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(Created page with "==Theorem== Let $\mathbb{T}$ be a time scale, $t \in \mathbb{T}^{\kappa}$, $f \colon \mathbb{T} \rightarrow \mathbb{R}$ delta differentiable, and $f(t...")
 
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==Theorem==
 
==Theorem==
Let $\mathbb{T}$ be a [[time scale]], $t \in \mathbb{T}^{\kappa}$, $f \colon \mathbb{T} \rightarrow \mathbb{R}$ [[delta derivative|delta differentiable]], and $f(t)f(\sigma(t)) \neq 0$. Then $\dfrac{1}{f}$ is delta differentiable and
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Let $\mathbb{T}$ be a [[time scale]], $t \in \mathbb{T}^{\kappa}$, $f,g \colon \mathbb{T} \rightarrow \mathbb{R}$ [[delta derivative|delta differentiable]], and $g(t)g(\sigma(t)) \neq 0$. Then $\dfrac{f}{g}$ is delta differentiable and
$$\left( \dfrac{1}{f} \right)^{\Delta}(t) = -\dfrac{f^{\Delta}(t)}{f(t)f(\sigma(t))},$$
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$$\left( \dfrac{f}{g} \right)^{\Delta}(t) = \dfrac{g(t)f^{\Delta}(t)-f(t)g^{\Delta}(t)}{g(t)g(\sigma(t))},$$
 
where $\sigma$ denotes the [[forward jump]].
 
where $\sigma$ denotes the [[forward jump]].
  
 
==References==
 
==References==
* {{BookReference|Dynamic Equations on Time Scales|2001|Martin Bohner|author2=Allan Peterson|prev=Delta derivative of product (2)|next=}}: Theorem 1.20 (iv)
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* {{BookReference|Dynamic Equations on Time Scales|2001|Martin Bohner|author2=Allan Peterson|prev=Delta derivative of product (2)|next=Delta derivative of classical polynomial}}: Theorem 1.20 (v)

Revision as of 05:44, 10 June 2016

Theorem

Let $\mathbb{T}$ be a time scale, $t \in \mathbb{T}^{\kappa}$, $f,g \colon \mathbb{T} \rightarrow \mathbb{R}$ delta differentiable, and $g(t)g(\sigma(t)) \neq 0$. Then $\dfrac{f}{g}$ is delta differentiable and $$\left( \dfrac{f}{g} \right)^{\Delta}(t) = \dfrac{g(t)f^{\Delta}(t)-f(t)g^{\Delta}(t)}{g(t)g(\sigma(t))},$$ where $\sigma$ denotes the forward jump.

References