document.write( "Question 1143597: A = 3cis(30)
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\n" ); document.write( "Find A*B and A + B
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\n" ); document.write( "I know A*B = 12cis(75)
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Algebra.Com's Answer #764455 by Edwin McCravy(20060) $\"\"$ $\"About$

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document.write( "There are two forms for complex numbers, rectangular (a+bi) and trigonometric\r\n" );
document.write( "form r∙cis(q).  \r\n" );
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document.write( "Rectangular form is easy to add and subtract but hard to multiply and divide.\r\n" );
document.write( "Trigonometric form is easy to multiply and divide but hard to add and subtract. \r\n" );
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document.write( "So we will change A and B to rectangular form and add them\r\n" );
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document.write( "We use our knowledge of sines and cosines of special angles 30° and 45°, to substitute for them:\r\n" );
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document.write( "We distribute to remove parentheses:\r\n" );
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document.write( "We swap the middle two terms to get the real terms together and the\r\n" );
document.write( "imaginary terms together:\r\n" );
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document.write( "Put parentheses around the real terms and factor out i from the imaginary terms:\r\n" );
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document.write( "You may leave it like that. Or, since the deminators are the same, you may combine the numerators over the common denominator\r\n" );
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document.write( "Edwin

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