Mark the correct alternative in the following:

The coordinates of the point on the ellipse 16x2+9y2=400 where the ordinate decreases at the same rate at which the abscissa increase, are:


Taking ellipse to be 16x2+9y2=400 instead of 46x2+9y2=400

Let E(x,y):16x2+9y2=400


Solving for y, we get


- (1)


Given that , we have to calculate x,y


Differentiating (1) with respect to t, we get



Substituting values, we get



Simplifying the equation, we get



Squaring both sides


256x2=9(400-16x2)


Solving the equation, we get


x2=9


x=±3


Substituting in (1), we get




By seeing the graph of E(x,y), we can conclude that the point has to lie in Ist or IIIrd quadrant, as only in these quadrants, the increase in abscissa leads to decrease in ordinate.


Hence the points are

1