At what point of the parabola x^2=9y is the abscissa three times that of ordinate ?
Let the ordinates of the required point is y
∴ abscissa=3y∴ The coordinates of the point are (3y,y)These point lies on the parabola x2=9y(3y)2=9y∴ 9y2=9y⇒ 9y(y−1)=0⇒ y−1=0 [∵ y≠0]⇒ y=1∴ abscissa=3×y=3Hence,the required point is (3,1).