Lösung 1.1:2e
Aus Online Mathematik Brückenkurs 2
(Unterschied zwischen Versionen)
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- | {{ | + | With the help of the square rule, we can expand the quadratic as |
- | < | + | |
- | {{ | + | |
+ | <math>\begin{align} | ||
+ | & f\left( x \right)=\left( x^{2}-1 \right)^{2}=\left( x^{2} \right)^{2}-2\centerdot x^{2}\centerdot 1+1^{2} \\ | ||
+ | & =x^{4}-2x^{2}+1 \\ | ||
+ | \end{align}</math> | ||
+ | |||
+ | |||
+ | When the function is written in this form, it is easy to differentiate term by term: | ||
+ | |||
+ | |||
+ | <math>\begin{align} | ||
+ | & {f}'\left( x \right)=\frac{d}{dx}\left( x^{4}-2x^{2}+1 \right) \\ | ||
+ | & =\frac{d}{dx}x^{4}-2\frac{d}{dx}x^{2}+\frac{d}{dx}1 \\ | ||
+ | & =4\centerdot x^{-1}-2\centerdot 2x^{-1}+0 \\ | ||
+ | & =4x^{3}-4x=4x\left( x^{2}-1 \right) \\ | ||
+ | \end{align}</math> |
Version vom 11:37, 10. Okt. 2008
With the help of the square rule, we can expand the quadratic as
\displaystyle \begin{align}
& f\left( x \right)=\left( x^{2}-1 \right)^{2}=\left( x^{2} \right)^{2}-2\centerdot x^{2}\centerdot 1+1^{2} \\
& =x^{4}-2x^{2}+1 \\
\end{align}
When the function is written in this form, it is easy to differentiate term by term:
\displaystyle \begin{align}
& {f}'\left( x \right)=\frac{d}{dx}\left( x^{4}-2x^{2}+1 \right) \\
& =\frac{d}{dx}x^{4}-2\frac{d}{dx}x^{2}+\frac{d}{dx}1 \\
& =4\centerdot x^{-1}-2\centerdot 2x^{-1}+0 \\
& =4x^{3}-4x=4x\left( x^{2}-1 \right) \\
\end{align}