What is the equation in standard form of the parabola with a focus at (11,-5) and a directrix of y= -19?
1 Answer
Dec 3, 2017
Explanation:
#"for any point "(x,y)" on the parabola"#
#"the focus and directrix are equidistant "#
#color(blue)"using the distance formula"#
#sqrt((x-11)^2+(y+5)^2)=|y+19|#
#color(blue)"squaring both sides"#
#(x-11)^2+(y+5)^2=(y+19)^2#
#rArrx^2-22x+121cancel(+y^2)+10y+25=cancel(y^2)+38y+361#
#rArr-28y=-x^2+22x+215#
#rArry=1/28x^2-11/14x-215/28#
