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1. Complex numbers A complex number z is defined as an ordered ...

1. Complex numbers A complex number z is defined as an ordered ...

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Take |z| > 1 <strong>as</strong> <strong>an</strong> illustration<br />

Geometric interpretation: Consider the tri<strong>an</strong>gle whose vertices are<br />

1, z <strong>an</strong>d |z|, by the Tri<strong>an</strong>gle Inequality, we have<br />

|z − 1| ≤<br />

<br />

<br />

<br />

<br />

<br />

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<br />

<br />

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<br />

|z| − 1<br />

+ z − |z| <br />

.<br />

The chord joining |z| <strong>an</strong>d z <strong>is</strong> always shorter th<strong>an</strong> the circular arc<br />

joining the same two points. Note that the arc length <strong>is</strong> given by<br />

|z| |Arg z|.<br />

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