document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=90683>Question 90683</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Determine whether each relation is a function.\r<BR>\n" );
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document.write( "x^2=1+y^2 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #65822 by </B><A HREF=/tutors/aboutme.mpl?userid=vertciel><B>vertciel(183)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=vertciel><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=65822\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This relation is not a function.\r<BR>\n" );
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document.write( "Proof:\r<BR>\n" );
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document.write( "x^2 = 1 + y^2\r<BR>\n" );
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document.write( "x = sqrt(1 + y^2)\r<BR>\n" );
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document.write( "Substitute y for 1:\r<BR>\n" );
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document.write( "x = sqrt(1 + 1^2)\r<BR>\n" );
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document.write( "  = sqrt(2)\r<BR>\n" );
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document.write( "Substitute y for -1:\r<BR>\n" );
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document.write( "x = sqrt(1 + (-1)^2)\r<BR>\n" );
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document.write( "  = sqrt(2)\r<BR>\n" );
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document.write( "Therefore, sqrt(2) has two y values: (&#8730;2, 1) and (&#8730;2, -1) </SPAN>\n" );
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