Processing Math: Done
Lösung 1.2:4b
Aus Online Mathematik Brückenkurs 2
(Unterschied zwischen Versionen)
K (Lösning 1.2:4b moved to Solution 1.2:4b: Robot: moved page) |
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- | {{ | + | To start with, we determine the first derivative and begin by using the product rule: |
- | + | ||
- | {{ | + | |
- | {{ | + | <math>\begin{align} |
- | < | + | & \frac{d}{dx}x\left( \sin \ln x+\cos \ln x \right) \\ |
- | {{ | + | & =\left( x \right)^{\prime }\centerdot \left( \sin \ln x+\cos \ln x \right)+x\centerdot \left( \sin \ln x+\cos \ln x \right)^{\prime } \\ |
+ | & =1\centerdot \left( \sin \ln x+\cos \ln x \right)+x\centerdot \left( \sin \ln x+\cos \ln x \right)^{\prime } \\ | ||
+ | \end{align}</math> | ||
+ | |||
+ | |||
+ | We divide up the differentiation of the second term in sections and use the chain rule: | ||
+ | |||
+ | |||
+ | |||
+ | <math>\begin{align} | ||
+ | & \left( \sin \ln x+\cos \ln x \right)^{\prime }=\left( \sin \ln x \right)^{\prime }+\left( \cos \ln x \right)^{\prime } \\ | ||
+ | & =\cos \ln x\centerdot \left( \ln x \right)^{\prime }-\sin \ln x\centerdot \left( \ln x \right)^{\prime } \\ | ||
+ | & =\cos \ln x\centerdot \frac{1}{x}-\sin \ln x\centerdot \frac{1}{x} \\ | ||
+ | \end{align}</math> | ||
+ | |||
+ | |||
+ | This means that | ||
+ | |||
+ | |||
+ | <math>\begin{align} | ||
+ | & \frac{d}{dx}x\left( \sin \ln x+\cos \ln x \right) \\ | ||
+ | & =\sin \ln x+\cos \ln x+\cos \ln x-\sin \ln x \\ | ||
+ | & =2\cos \ln x \\ | ||
+ | \end{align}</math> | ||
+ | |||
+ | |||
+ | The second derivative is | ||
+ | |||
+ | |||
+ | <math>\begin{align} | ||
+ | & \frac{d}{dx}2\cos \ln x=-2\sin \ln x\centerdot \left( \ln x \right)^{\prime } \\ | ||
+ | & =-2\sin \ln x\centerdot \frac{1}{x}=-\frac{2\sin \ln x}{x} \\ | ||
+ | \end{align}</math> |
Version vom 14:15, 12. Okt. 2008
To start with, we determine the first derivative and begin by using the product rule:
sinlnx+coslnx
=
x
sinlnx+coslnx
+x
sinlnx+coslnx
=1
sinlnx+coslnx
+x
sinlnx+coslnx
We divide up the differentiation of the second term in sections and use the chain rule:
sinlnx+coslnx
=
sinlnx
+
coslnx
=coslnx
lnx
−sinlnx
lnx
=coslnx
x1−sinlnx
x1
This means that
sinlnx+coslnx
=sinlnx+coslnx+coslnx−sinlnx=2coslnx
The second derivative is
lnx
=−2sinlnx
x1=−x2sinlnx