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MathsHardMCQ2020 ยท 05 Sep Shift 1

Q57.If the point P on the curve, 4x2 + 5y2 = 20 is farthest from the point Q(0, โˆ’4), then PQ2 is equal to (1) 36 (2) 48 (3) 21 (4) 29

What This Question Tests

This problem involves setting up the square of the distance from a point on an ellipse to a fixed point, expressing it in terms of a single variable, and then using calculus (differentiation) to find the maximum distance.

Concepts Tested

Equation of an ellipseDistance formula in 2DFinding maximum/minimum using derivatives

Formulas Used

Distance formula D^2 = (x2-x1)^2 + (y2-y1)^2

Derivative for extrema d(D^2)/dy = 0

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