document.write( "Question 389436: HOW TO DETERMINE i2=−1 FROM THE EULER`S EQUATION USING LOGARITHM/WITHOUT LOGARITHM? PLEASE TELL ME IN DETAILS. \n" ); document.write( "
Algebra.Com's Answer #275959 by richard1234(7193)\"\" \"About 
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\"i%5E2+=+-1\" by definition. Or, we use Euler's formula:\r
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\n" ); document.write( "\n" ); document.write( "\"e%5Eix+=+cis+x+=+cos+x+%2B+i+sin+x\"\r
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\n" ); document.write( "\n" ); document.write( "Letting \"x+=+pi%2F2\",\r
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\n" ); document.write( "\n" ); document.write( "\"e%5Ei%28pi%2F2%29+=+cos+%28pi%2F2%29+%2B+i+sin+%28pi%2F2%29+=+i\"\r
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\n" ); document.write( "\n" ); document.write( "Squaring both sides,\r
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\n" ); document.write( "\n" ); document.write( "\"e%5Ei%28pi%29+=+cos+%28pi%29+%2B+i+sin+%28pi%29+=+-1\"\r
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\n" ); document.write( "\n" ); document.write( "This implies \"i%5E2+=+-1\".
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