document.write( "Question 1209260: Find the equation of the tangents drawn from the point (4, 7) to the circle:
\n" ); document.write( " (x - 2)² + y² + 4y = 0.\r
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Algebra.Com's Answer #848002 by AnlytcPhil(1806) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "Yes it can be done that way:\r\n" );
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document.write( "We use the point-slope formula for the equation of a line through (4,7) \r\n" );
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document.write( "Substitute in\r\n" );
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document.write( "That simplifies to the quadratic in x²\r\n" );
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document.write( "The point of tangency can be thought of as where \r\n" );
document.write( "the tangent line intersects the circle TWICE at\r\n" );
document.write( "the same point.  So both solutions must be equal.\r\n" );
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document.write( "So we set the  \r\n" );
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document.write( "That simplifies to \r\n" );
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document.write( "The equation of the slanted tangent line is\r\n" );
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document.write( "Which simplifies to what I got above.\r\n" );
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document.write( "Edwin

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