at what points of the ellipse 16x^2 + 9y^2 = 400 does the ordinate decrease at the same rate at which the abcissa increases ??
Let (x, y) be the required point.
Then
Consider the given curve
......(!)
Differentiate the above function with respect to x,
Substitute the value in the above equation, we have
Now substitute, in the equation of the curve (1), we have
Now for the value ,
Now for the value ,
Hence the required points are