Lösung 2.3:10c
Aus Online Mathematik Brückenkurs 1
K (Lösning 2.3:10c moved to Solution 2.3:10c: Robot: moved page) |
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- | {{ | + | The expression |
- | < | + | <math>\text{1}\ge x\ge \text{ }y^{\text{2}}</math> |
- | {{ | + | means that we have a region which is defined by the two inequalities |
- | {{ | + | <math>\text{1}\ge x\text{ }</math> |
- | < | + | and |
- | {{ | + | <math>x\ge \text{ }y^{\text{2}}</math>. The first inequality gives us the region to the left of the line |
+ | <math>x=\text{1}</math>. If the other inequality had been instead | ||
+ | <math>y=x^{\text{2}}</math>, we would have a region above the parabola | ||
+ | <math>y=x^{\text{2}}</math>, but in our case | ||
+ | <math>x</math> | ||
+ | and | ||
+ | <math>y</math> | ||
+ | have reversed roles, so the inequality | ||
+ | <math>x\ge \text{ }y^{\text{2}}</math> | ||
+ | defines the same type of parabolic region, but with the | ||
+ | <math>x</math> | ||
+ | - and | ||
+ | <math>y</math> | ||
+ | -axes having changed place. | ||
+ | |||
[[Image:2_3_10_c1.gif|center]] | [[Image:2_3_10_c1.gif|center]] | ||
+ | Together, the inequalities define the region that is bordered on the left by the parabola and on the right by the line. | ||
[[Image:2_3_10_c2.gif|center]] | [[Image:2_3_10_c2.gif|center]] |
Version vom 12:47, 21. Sep. 2008
The expression \displaystyle \text{1}\ge x\ge \text{ }y^{\text{2}} means that we have a region which is defined by the two inequalities \displaystyle \text{1}\ge x\text{ } and \displaystyle x\ge \text{ }y^{\text{2}}. The first inequality gives us the region to the left of the line \displaystyle x=\text{1}. If the other inequality had been instead \displaystyle y=x^{\text{2}}, we would have a region above the parabola \displaystyle y=x^{\text{2}}, but in our case \displaystyle x and \displaystyle y have reversed roles, so the inequality \displaystyle x\ge \text{ }y^{\text{2}} defines the same type of parabolic region, but with the \displaystyle x - and \displaystyle y -axes having changed place.
Together, the inequalities define the region that is bordered on the left by the parabola and on the right by the line.