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Let .
Then, by exercise (ii). Suppose both x, y 0. Let an be given Choose such that and ![](../images/Math%20Images/Section-1.7_1_clip_image002_0013.gif)
Note that Then,
![](../images/Math%20Images/Section-1.7_2_clip_image002.gif) |
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Hence, . This proves (ii) when The case when is easy and is left as an exercise. |
(iii) |
To prove (iii), we have to show that given an and such that |
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Since and ,we have such that
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