document.write( "Question 266674: the equation of a tangent line to the curve x^2+y^2=169 at the point (5,-12) is? \n" ); document.write( "
Algebra.Com's Answer #195914 by drk(1908)\"\" \"About 
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step 1 - we take a derivative of both sides and get
\n" ); document.write( "\"2x+%2B+2y%28dy%2Fdx%29+=+0\"
\n" ); document.write( "step 2 - solve for dy/dx
\n" ); document.write( "\"%28dy%2Fdx%29+=+-x%2Fy\"
\n" ); document.write( "step 3 - put your coordinates in and get
\n" ); document.write( " \"%28dy%2Fdx%29+=+-5%2F-12\"
\n" ); document.write( "---
\n" ); document.write( "so, the slope is
\n" ); document.write( "dy/dx = m = 5/12
\n" ); document.write( "---
\n" ); document.write( "step 4 - using slope and our coordinate as well as y = mx + b, we get
\n" ); document.write( "\"y+=+mx+%2B+b\"
\n" ); document.write( "and then
\n" ); document.write( "\"-12+=+%285%2F12%29%2A5+%2B+b\"
\n" ); document.write( "solving for b, we get
\n" ); document.write( "\"-169%2F12+=+b\"
\n" ); document.write( "---
\n" ); document.write( "step 5 - final equation is
\n" ); document.write( "\"y+=+%285%2F12%29x+-+169%2F12\"
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