document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=358061>Question 358061</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi<BR>\n" );
document.write( "     Quick question if somebody would be so kind as to walk me through it\r<BR>\n" );
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document.write( "Find the equation of the tangent to the circle\r<BR>\n" );
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document.write( "x^2+y^2-4y-1=0\r<BR>\n" );
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document.write( "The the point (2,1)\r<BR>\n" );
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document.write( "Thanks in advance </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #255596 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=255596\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find the equation of the tangent to the circle <BR>\n" );
document.write( "x^2+y^2-4y-1=0 <BR>\n" );
document.write( "The the point (2,1)<BR>\n" );
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document.write( "Find the derivative.<BR>\n" );
document.write( "2x + 2yy' - 4y' = 0<BR>\n" );
document.write( "y'(2y-4) = -2x<BR>\n" );
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document.write( "y' = -2x/(2y-4)<BR>\n" );
document.write( "This is the slope at every point (x,y)<BR>\n" );
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document.write( "Let x = 2 ; Let y = 1 to find the slope at (2,1)<BR>\n" );
document.write( "y' = -4/(-2) = 2<BR>\n" );
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document.write( "Find the line with slope = 2 passing thru (2,1)<BR>\n" );
document.write( "1 = -2(2)+b<BR>\n" );
document.write( "b = 5<BR>\n" );
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document.write( "Equation of the tangent at (2,1)<BR>\n" );
document.write( "y = 2x+5<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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