document.write( "Question 946847: Write an equation for the line tangent to the circle x2 + y2 = 17, at the point (4, 1). \n" ); document.write( "

Algebra.Com's Answer #577652 by Fombitz(32388) $\"\"$ $\"About$

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The slope of the tangent line is equal to the derivative at the point.
\n" ); document.write( " $\"2xdx%2B2ydy=0\"$
\n" ); document.write( " $\"2ydy=-2xdx\"$
\n" ); document.write( " $\"m=dy%2Fdx=-x%2Fy\"$
\n" ); document.write( "So at (4,1), the slope is equal to,
\n" ); document.write( " $\"m=-4%2F1=-4\"$
\n" ); document.write( "Using the point-slope form of a line,
\n" ); document.write( " $\"y-1=-%284%29%28x-4%29\"$
\n" ); document.write( " $\"y-1=-4x%2B16\"$
\n" ); document.write( " $\"highlight%28y=-4x%2B17%29\"$
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