(New page: Express each of the following complex numbers in polar form, and plot them in the complex plane, indicating the magnitude and angle of each number. A) <math> 1 + jsqrt(3)</math>)
 
 
(24 intermediate revisions by the same user not shown)
Line 1: Line 1:
 
Express each of the following complex numbers in polar form, and plot them in the complex plane, indicating the magnitude and angle of each number.  
 
Express each of the following complex numbers in polar form, and plot them in the complex plane, indicating the magnitude and angle of each number.  
  
A) <math> 1 + jsqrt(3)</math>
+
A) <math> 1 + j\sqrt{3}</math>
 +
 
 +
<math> r = \sqrt{1^2 + \sqrt{3}^2} = \sqrt{4} = 2</math>
 +
 
 +
<math>\theta = arctan(\sqrt{3}/1) = arctan(\sqrt{3}) = \frac{\pi}{3}</math>
 +
 
 +
Therefore the polar form of this complex number is: <math>2e^{j\frac{\pi}{3}}</math>
 +
 
 +
B) <math> -5 </math>
 +
 
 +
<math> r = 5 </math>
 +
 
 +
<math> \theta = \pi </math>
 +
 
 +
Therefore the polar form of this complex number is: <math>5e^{j\pi}</math>
 +
 
 +
F) <math> (1 + j)^{5} </math>
 +
 
 +
<math> r = \sqrt{1^2 + 1^2} = \sqrt{2} </math>
 +
 
 +
<math> \theta = \frac{\pi}{4} </math>
 +
 
 +
<math> (1 + j) = \sqrt{2}e^{j\frac{\pi}{4}} </math>
 +
 
 +
<math> (1 + j)^{5} = (\sqrt{2}e^{j\frac{\pi}{4}})^{5} = 2^{\frac{5}{2}}e^{j\frac{5\pi}{4}} = 4\sqrt{2}e^{j(\pi + \frac{\pi}{4})} =4\sqrt{2}e^{j\pi}e^{j\frac{\pi}{4}} = -4(\sqrt{2}e^{j\frac{\pi}{4}}) = -4(1 + j)</math>
 +
 
 +
Therefore the polar form of this complex number is: <math> -4(\sqrt{2}e^{j\frac{\pi}{4}}) </math>
 +
 
 +
I) <math> \frac{1 + j\sqrt{3}}{\sqrt{3} + j} </math>
 +
 
 +
<math> r = 2 </math>
 +
 
 +
<math> Equation 1 = 1 + j\sqrt{3}  =>  \theta_{1} = \frac{\pi}{3} </math>
 +
 
 +
<math> Equation 2 = \sqrt{3} + j  =>  \theta_{2} = \frac{\pi}{6} </math>
 +
 
 +
<math> \frac{2e^{j\frac{\pi}{3}}}{2e^{j\frac{\pi}{6}}} = \frac{e^{j\frac{\pi}{3}}}{e^{j\frac{\pi}{6}}} = e^{j(\frac{\pi}{3} - \frac{\pi}{6})} = e^{j\frac{\pi}{6}}</math>
 +
 
 +
Therefore the polar form of this complex number is: <math> e^{j\frac{\pi}{6}}</math>

Latest revision as of 00:33, 13 June 2008

Express each of the following complex numbers in polar form, and plot them in the complex plane, indicating the magnitude and angle of each number.

A) $ 1 + j\sqrt{3} $

$ r = \sqrt{1^2 + \sqrt{3}^2} = \sqrt{4} = 2 $

$ \theta = arctan(\sqrt{3}/1) = arctan(\sqrt{3}) = \frac{\pi}{3} $

Therefore the polar form of this complex number is: $ 2e^{j\frac{\pi}{3}} $

B) $ -5 $

$ r = 5 $

$ \theta = \pi $

Therefore the polar form of this complex number is: $ 5e^{j\pi} $

F) $ (1 + j)^{5} $

$ r = \sqrt{1^2 + 1^2} = \sqrt{2} $

$ \theta = \frac{\pi}{4} $

$ (1 + j) = \sqrt{2}e^{j\frac{\pi}{4}} $

$ (1 + j)^{5} = (\sqrt{2}e^{j\frac{\pi}{4}})^{5} = 2^{\frac{5}{2}}e^{j\frac{5\pi}{4}} = 4\sqrt{2}e^{j(\pi + \frac{\pi}{4})} =4\sqrt{2}e^{j\pi}e^{j\frac{\pi}{4}} = -4(\sqrt{2}e^{j\frac{\pi}{4}}) = -4(1 + j) $

Therefore the polar form of this complex number is: $ -4(\sqrt{2}e^{j\frac{\pi}{4}}) $

I) $ \frac{1 + j\sqrt{3}}{\sqrt{3} + j} $

$ r = 2 $

$ Equation 1 = 1 + j\sqrt{3} => \theta_{1} = \frac{\pi}{3} $

$ Equation 2 = \sqrt{3} + j => \theta_{2} = \frac{\pi}{6} $

$ \frac{2e^{j\frac{\pi}{3}}}{2e^{j\frac{\pi}{6}}} = \frac{e^{j\frac{\pi}{3}}}{e^{j\frac{\pi}{6}}} = e^{j(\frac{\pi}{3} - \frac{\pi}{6})} = e^{j\frac{\pi}{6}} $

Therefore the polar form of this complex number is: $ e^{j\frac{\pi}{6}} $

Alumni Liaison

Correspondence Chess Grandmaster and Purdue Alumni

Prof. Dan Fleetwood