Maths-
General
Easy
Question
The point on the ellipse 16x2 + 9y2 = 400 where ordinate decrease at the same rate at which the abscissa increases is
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Hint:
We are given the equation of ellipse. We are given that the rate of decrease of ordinante is same as the rate of increase of abscissa. Rate means change w.r.t the time. To find the rate of change of quantity, we take it's derivative w.r.t time. We have to find the point at which the rate is as given above.
The correct answer is:
The given equation of ellipse is 16x2 + 9y2 = 400
Ordinate means distance of the point from x-axis. It is given by y coordinate.
Abscissa means distance of the point from the y-axis. It is given by x coordinate.
We are given that, .....(1)
We will take the derivate of the equation of ellipse w.r.t time.
Now, to find the points we will substitute the value of x in the equation of ellipse.
Taking square roots of both sides we get,
So, the points satisfying the given condition are
This is the only point that matches the option .
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For such questions, we should know how to find the derivates. We should know the concept of abscissa and ordinate.
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