document.write( "Question 1152368: √x+√(1-x)+√(x(1-x))=1 \n" ); document.write( "
Algebra.Com's Answer #774575 by ikleyn(52781)\"\" \"About 
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document.write( "\"sqrt%28x%29\" + \"sqrt%281-x%29\" + \"sqrt%28x%2A%281-x%29%29\" = 1.      (1)\r\n" );
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document.write( "The domain, where all included functions are defined, is the segment  [0,1].\r\n" );
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document.write( "Two obvious solutions to the given equation in this domain are x= 0  and  x= 1.\r\n" );
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document.write( "Below I will show that the given equation HAS NO other solutions.\r\n" );
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document.write( "Indeed, let  0 < x < 1.\r\n" );
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document.write( "Then        \"sqrt%28x%29\" is defined and is positive number  \"sqrt%28x%29\" > 0.\r\n" );
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document.write( "Similarly,  \"sqrt%281-x%29\" is defined and is positive number  \"sqrt%281-x%29\" > 0.\r\n" );
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document.write( "    For any two real positive numbers \"a\" and \"b\" the following inequality is valid\r\n" );
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document.write( "        a + b > \"sqrt%28a%5E2+%2B+b%5E2%29\".    (2)\r\n" );
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document.write( "    To prove it, square both sides. You will get\r\n" );
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document.write( "        a^2 + 2ab + b^2 > a^2 + b^2,\r\n" );
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document.write( "    which is valid for all positive \"a\" and \"b\".\r\n" );
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document.write( "Now apply the inequality (2) for  a= \"sqrt%28x%29\"  and  b= \"sqrt%281-x%29\".  You will get\r\n" );
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document.write( "    \"sqrt%28x%29\" + \"sqrt%281-x%29\" > \"sqrt%28%28sqrt%28x%29%29%5E2+%2B+%28sqrt%281-x%29%29%5E2%29\" = \"sqrt%28x+%2B+1-x%29\" = \"sqrt%281%29\" = 1.\r\n" );
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document.write( "Thus,  the sum  \"sqrt%28x%29\" + \"sqrt%281-x%29\"  at  0 < x < 1  is just greater than 1.\r\n" );
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document.write( "With the added positive addend  \"sqrt%28x%2A%281-x%29%29\",  the sum  \"sqrt%28x%29\" + \"sqrt%281-x%29\" + \"sqrt%28x%2A%281-x%29%29\"  is just even more than 1.  \r\n" );
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document.write( "Therefore,  the sum  \"sqrt%28x%29\" + \"sqrt%281-x%29\" + \"sqrt%28x%2A%281-x%29%29\"  can not be equal to 1  at  0 < x < 1.\r\n" );
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document.write( "Thus, it is  PROVED that the given equation has no solutions inside the segment [0,1].  \r\n" );
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document.write( "So, the endpoints  x= 0  and  x= 1 are the only solutions.\r\n" );
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