document.write( "Question 1208932: I would like to see the prove for these two questions. \r
\n" ); document.write( "\n" ); document.write( "1. If a > 0, show that the solution set of the inequality x^2 < a consists of all numbers x for which -sqrt{a} < x < sqrt{a}.\r
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Algebra.Com's Answer #847465 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "1. If \"a+%3E+0\", show that the solution set of the inequality \"x%5E2+%3C+a\" consists of all numbers x for which \"-sqrt%28a%29+%3C+x+%3C+sqrt%28a%29\".\r\n" );
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document.write( "Let us assume for contradiction that there exists x such that\r\n" );
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document.write( "\"a+%3E+0%22%22%22+such+that+%7B%7B%7Bx%5E2+%3C+a\", yet \"x+%3C+-sqrt%28a%29\"\r\n" );
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document.write( "Since \"x+%3C+-sqrt%28a%29\", x is negative for it is less than a negative number.\r\n" );
document.write( "Then -x is a positive number and \r\n" );
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document.write( "\"-x+%3E+sqrt%28a%29\" [both sides are positive]. Therefore,\r\n" );
document.write( "\"x%5E2+%3E+a\" which contradicts \"x%5E2+%3C+a\".\r\n" );
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document.write( "That's half the proof.\r\n" );
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document.write( "Now assume for contradiction that there exists x such that\r\n" );
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document.write( "\"a+%3E+0\" such that \"x%5E2+%3C+a\", yet \"x+%3E+sqrt%28a%29\"\r\n" );
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document.write( "Since \"x+%3E+sqrt%28a%29\", \"x%5E2+%3E+a\" which contradicts \"x%5E2+%3C+a\" \r\n" );
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document.write( "Thus the proof is done, and \r\n" );
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document.write( "\"a+%3E+0\", \"x%5E2+%3C+a\" implies \"-sqrt%28a%29+%3C+x+%3C+sqrt%28a%29\".\r\n" );
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document.write( "2. If \"a+%3E+0\", show that the solution set of the inequality \"x%5E2+%3E+a\"\r\n" );
document.write( "consists of all numbers x for which \"x+%3C+-sqrt%28a%29\" or \"x+%3E+sqrt%28a%29\".\r\n" );
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document.write( "Assume for contradiction that there exists x such that\r\n" );
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document.write( "\"a+%3E+0\" and \"x%5E2+%3E+a\", yet \"-sqrt%28a%29%3Cx%3C0\" \r\n" );
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document.write( "Then both \"-sqrt%28a%29\" and x are negative numbers, and thus -x is a \r\n" );
document.write( "positive number.\r\n" );
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document.write( "\"-sqrt%28a%29%3Cx%3C0\" implies \"0%3C-x%3Csqrt%28a%29\" thus \"x%5E2%3Ca\"\r\n" );
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document.write( "which contradicts \"x%5E2%3Ea\"\r\n" );
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document.write( "That's half the proof. \r\n" );
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document.write( "Next, assume for contradiction that there exists x such that\r\n" );
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document.write( "\"a+%3E+0\" and \"x%5E2+%3E+a\", yet \"0%3C=x%3Csqrt%28a%29\" \r\n" );
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document.write( "Then \"0%3C=x%3Csqrt%28a%29\" implies \"x%5E2%3Ca\" which contradicts \"x%5E2%3Ea\".\r\n" );
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document.write( "Then \"a+%3E+0\", \"x%5E2+%3E+a\" implies \"matrix%281%2C3%2Cx%3C-sqrt%28a%29%2C+or%2C+x%3Esqrt%28a%29%29\"\r\n" );
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document.write( "Edwin
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