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A man plans to jump and climb the stairs. The path (as shown in the figure) he moves for the first jump is given by y=y(x)=x+2x−3x2y = y(x) = x + \sqrt{2x - 3x^2} where 'x' (in meters) is the horizontal distance moved and 'y' (in meters) is the corresponding height. Assuming that his initial point is at origin.

Figure for CUET Mathematics 2022 6 Aug Shift 2 question 41 (Calculus)

Based on the above information answer the Questions

The value of xx for which dydx=0\frac{dy}{dx} = 0, is

Solution

✅ Correct Option: 1

dydx=1+1−3x2x−3x2\frac{dy}{dx} = 1 + \frac{1 - 3x}{\sqrt{2x - 3x^2}}.

Setting this to zero: 2x−3x2=3x−1\sqrt{2x - 3x^2} = 3x - 1 (need x≥1/3x \geq 1/3).

Squaring: 2x−3x2=9x2−6x+12x - 3x^2 = 9x^2 - 6x + 1, giving 12x2−8x+1=012x^2 - 8x + 1 = 0.

x=8±424=12x = \frac{8 \pm 4}{24} = \frac{1}{2} or 16\frac{1}{6}. Since x≥1/3x \geq 1/3, x=12x = \frac{1}{2}.

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