document.write( "Question 1020219: How may i prove this using direct proof?\r
\n" ); document.write( "\n" ); document.write( "Let x,y be real numbers.\r
\n" ); document.write( "\n" ); document.write( " $\"+x%5E2%2By%5E2+%3E=+2xy+\"$ \r
\n" ); document.write( "\n" ); document.write( "Please help!!\r
\n" ); document.write( "\n" ); document.write( "thank you! \n" ); document.write( "

Algebra.Com's Answer #636126 by robertb(5830) $\"\"$ $\"About$

You can put this solution on YOUR website!
For all real numbers x, y, it is always true that \r
\n" ); document.write( "\n" ); document.write( " $\"%28x-y%29%5E2%3E=0\"$ \r
\n" ); document.write( "\n" ); document.write( "Expanding the left side of the inequality, \r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2+-+2xy+%2By%5E2+%3E=+0\"$ \r
\n" ); document.write( "\n" ); document.write( "==> $\"x%5E2+%2B+y%5E2+%3E=+2xy\"$ after transposition.\r
\n" ); document.write( "\n" ); document.write( "And the statement is proved. \n" ); document.write( "

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