document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1080222>Question 1080222</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Which of these is the equation for a line tangent to the circle x^2 + y^2 = 20 at point (2, -4)?\r<BR>\n" );
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document.write( "y = ½x + &#8730;20<BR>\n" );
document.write( "y = 2x – 5<BR>\n" );
document.write( "y = 2x + &#8730;20<BR>\n" );
document.write( "y = ½x – 5<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #694408 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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/cgi-bin/show-face.mpl?user=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=694408\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> To find the slope, calculate the derivative at the point.<BR>\n" );
document.write( "Using implicit differentiation,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2xdx%2B2ydy=0 ALIGN=MIDDLE  ALT=\"2xdx%2B2ydy=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ydy=-xdx ALIGN=MIDDLE  ALT=\"ydy=-xdx\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=dy%2Fdx=-x%2Fy ALIGN=MIDDLE  ALT=\"dy%2Fdx=-x%2Fy\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So at (2,-4),<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m=dy%2Fdx=-2%2F-4=1%2F2 ALIGN=MIDDLE  ALT=\"m=dy%2Fdx=-2%2F-4=1%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Using the point-slope form of a line,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y-%28-4%29=%281%2F2%29%28x-2%29 ALIGN=MIDDLE  ALT=\"y-%28-4%29=%281%2F2%29%28x-2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y%2B4=x%2F2-1 ALIGN=MIDDLE  ALT=\"y%2B4=x%2F2-1\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y=x%2F2-5 ALIGN=MIDDLE  ALT=\"y=x%2F2-5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/display-illustration.mpl?tutor=Fombitz&illustration_name=dr1.JPG\">. </SPAN>\n" );
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