Prove 2 segments in complex plane have the same length












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I saw a solution which stated that we simultaneously show that two segments in the complex plane $A$ and $B$ have the same length and are perpendicular if we can show that $B=iA$.

I get that the rotation by $i$ implies they're perpendicular but why does showing this imply they're of the same length?










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  • 2




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    One of my rules in complex analysis is if I have a problem that I don't have a better approach to, I write $z=x+iy$ and see where that leads. That would work here.
    $endgroup$
    – Ross Millikan
    Dec 4 '18 at 3:14
















-1












$begingroup$


I saw a solution which stated that we simultaneously show that two segments in the complex plane $A$ and $B$ have the same length and are perpendicular if we can show that $B=iA$.

I get that the rotation by $i$ implies they're perpendicular but why does showing this imply they're of the same length?










share|cite|improve this question











$endgroup$








  • 2




    $begingroup$
    One of my rules in complex analysis is if I have a problem that I don't have a better approach to, I write $z=x+iy$ and see where that leads. That would work here.
    $endgroup$
    – Ross Millikan
    Dec 4 '18 at 3:14














-1












-1








-1





$begingroup$


I saw a solution which stated that we simultaneously show that two segments in the complex plane $A$ and $B$ have the same length and are perpendicular if we can show that $B=iA$.

I get that the rotation by $i$ implies they're perpendicular but why does showing this imply they're of the same length?










share|cite|improve this question











$endgroup$




I saw a solution which stated that we simultaneously show that two segments in the complex plane $A$ and $B$ have the same length and are perpendicular if we can show that $B=iA$.

I get that the rotation by $i$ implies they're perpendicular but why does showing this imply they're of the same length?







complex-analysis geometry






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edited Dec 4 '18 at 10:59









user376343

3,4133826




3,4133826










asked Dec 4 '18 at 3:05









john fowlesjohn fowles

1,203817




1,203817








  • 2




    $begingroup$
    One of my rules in complex analysis is if I have a problem that I don't have a better approach to, I write $z=x+iy$ and see where that leads. That would work here.
    $endgroup$
    – Ross Millikan
    Dec 4 '18 at 3:14














  • 2




    $begingroup$
    One of my rules in complex analysis is if I have a problem that I don't have a better approach to, I write $z=x+iy$ and see where that leads. That would work here.
    $endgroup$
    – Ross Millikan
    Dec 4 '18 at 3:14








2




2




$begingroup$
One of my rules in complex analysis is if I have a problem that I don't have a better approach to, I write $z=x+iy$ and see where that leads. That would work here.
$endgroup$
– Ross Millikan
Dec 4 '18 at 3:14




$begingroup$
One of my rules in complex analysis is if I have a problem that I don't have a better approach to, I write $z=x+iy$ and see where that leads. That would work here.
$endgroup$
– Ross Millikan
Dec 4 '18 at 3:14










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$begingroup$

Let $x,y$ be the endpoints of $A$; so $ix,iy$ are the endpoints of $B$ (here, $x,y in mathbb{C}$). In the complex plane, the length of $A$ is just $|y - x|$; the length of $B$ is then:
$$|iy - ix| = |i(y - x)| = |i| |y - x| = |y-x|.$$






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    1 Answer
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    1 Answer
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    oldest

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    3












    $begingroup$

    Let $x,y$ be the endpoints of $A$; so $ix,iy$ are the endpoints of $B$ (here, $x,y in mathbb{C}$). In the complex plane, the length of $A$ is just $|y - x|$; the length of $B$ is then:
    $$|iy - ix| = |i(y - x)| = |i| |y - x| = |y-x|.$$






    share|cite|improve this answer









    $endgroup$


















      3












      $begingroup$

      Let $x,y$ be the endpoints of $A$; so $ix,iy$ are the endpoints of $B$ (here, $x,y in mathbb{C}$). In the complex plane, the length of $A$ is just $|y - x|$; the length of $B$ is then:
      $$|iy - ix| = |i(y - x)| = |i| |y - x| = |y-x|.$$






      share|cite|improve this answer









      $endgroup$
















        3












        3








        3





        $begingroup$

        Let $x,y$ be the endpoints of $A$; so $ix,iy$ are the endpoints of $B$ (here, $x,y in mathbb{C}$). In the complex plane, the length of $A$ is just $|y - x|$; the length of $B$ is then:
        $$|iy - ix| = |i(y - x)| = |i| |y - x| = |y-x|.$$






        share|cite|improve this answer









        $endgroup$



        Let $x,y$ be the endpoints of $A$; so $ix,iy$ are the endpoints of $B$ (here, $x,y in mathbb{C}$). In the complex plane, the length of $A$ is just $|y - x|$; the length of $B$ is then:
        $$|iy - ix| = |i(y - x)| = |i| |y - x| = |y-x|.$$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 4 '18 at 3:10









        plattyplatty

        3,370320




        3,370320






























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