document.write( "Question 1127558: The equation of a curve is y=3+4x-x^2.
\n" );
document.write( "Show that the equation of the normal to the curve at a point (3,6) is 2y=x+9.
\n" );
document.write( "Given that the normal meets the coordinate axes at points A and B ,find the coordinates of midpoint of AB. \n" );
document.write( "
Algebra.Com's Answer #743968 by greenestamps(13200)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "The function is y = -x^2+4x+3 \n" ); document.write( "The derivative is -2x+4 \n" ); document.write( "The derivative at x=3 is -2(3)+4 = -2; so the slope of the curve at x=3 is -2. \n" ); document.write( "The slope of the normal to the curve at x=3 is the negative reciprocal, 1/2. \n" ); document.write( "The equation of the line with slope 1/2 passing through (3,6) is y = (1/2)x+9/2, or 2y = x+9. \n" ); document.write( "The x-intercept of the normal (set y=0) is (-9,0); the y-intercept (set x=0) is (0,9/2). \n" ); document.write( "The midpoint of the segment with endpoints (-9,0) and (0,9/2) is (-9/2,9/4). \n" ); document.write( "A graph.... \n" ); document.write( " |