document.write( "Question 122065: Find (1 / sq. rt. 2 + i / sq. rt. 2) ^ 8 \r
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\n" ); document.write( "\n" ); document.write( "a.) -8\r
\n" ); document.write( "\n" ); document.write( "b.) 256\r
\n" ); document.write( "\n" ); document.write( "c.) 8\r
\n" ); document.write( "\n" ); document.write( "d.) 1\r
\n" ); document.write( "\n" ); document.write( "e.) None of these
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Algebra.Com's Answer #89603 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\"%281%2Fsqrt%282%29%2Bi%2Fsqrt%282%29%29%5E8\" Start with the given expression\r
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\n" ); document.write( "\n" ); document.write( "It's very useful to note that \"cos%28pi%2F4%29=1%2Fsqrt%282%29\" and \"sin%28pi%2F4%29=1%2Fsqrt%282%29\" . So the expression is equivalent to \r
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\n" ); document.write( "\n" ); document.write( "\"%28cos%28pi%2F4%29%2Bi%2Asin%28pi%2F4%29%29%5E8\" \r
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\n" ); document.write( "\n" ); document.write( "Now we're going to use De Moivre's theorem to solve this problem.\r
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\n" ); document.write( "\n" ); document.write( "Remember, De Moivre's theorem states: \"%28cos%28x%29%2Bi%2Asin%28x%29%29%5En=cos%28n%2Ax%29%2Bi%2Asin%28n%2Ax%29\"\r
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\n" ); document.write( "\n" ); document.write( "So using De Moivre's theorem we get\r
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\n" ); document.write( "\n" ); document.write( "\"cos%288%2Api%2F4%29%2Bi%2Asin%288%2Api%2F4%29\" \r
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\n" ); document.write( "\n" ); document.write( "\"cos%282pi%29%2Bi%2Asin%282pi%29\" Multiply \"8\" and \"pi%2F4\" to get \"8pi%2F4\". Now reduce to get \"2pi\"\r
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\n" ); document.write( "\n" ); document.write( "\"1%2B0i\" Take the cosine of \"2pi\" to get 1. Take the sine of \"2pi\" to get 0.\r
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\n" ); document.write( "\n" ); document.write( "\"1\" Remove the zero term\r
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\n" ); document.write( "\n" ); document.write( "So \"%281%2Fsqrt%282%29%2Bi%2Fsqrt%282%29%29%5E8\" simplifies to 1. \r
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\n" ); document.write( "\n" ); document.write( "In other words, \"%281%2Fsqrt%282%29%2Bi%2Fsqrt%282%29%29%5E8=1\"\r
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\n" ); document.write( "\n" ); document.write( "So the answer is D)
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