Basic complex numbers

• March 31st 2008, 03:33 AM
Basic complex numbers
Hey guys was just wondering if someone could explain why 5i/10i doesnt equal 0.5. My calculator says it is negative 0.5. Should the i's cancel each other out. Please give a detailed explanation, i cant find anything in my text books
• March 31st 2008, 05:04 AM
topsquark
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Hey guys was just wondering if someone could explain why 5i/10i doesnt equal 0.5. My calculator says it is negative 0.5. Should the i's cancel each other out. Please give a detailed explanation, i cant find anything in my text books

Using the "correct" method (rationalizing the denominator):
$\frac{5i}{10i}$

$= \frac{5i}{10i} \cdot \frac{-10i}{-10i} = \frac{-50i^2}{-100i^2} = \frac{50}{100} = \frac{1}{2}$
so you are putting something into your calculator wrong. (Or the calculator needs to be replaced!)

-Dan
• March 31st 2008, 05:17 AM
mr fantastic
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