CUET Preparation Today
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What is the maximum height of the plant? |
12 cm 10 cm 8 cm 6 cm |
8 cm |
$y=4x-\frac{x^2}{2}$ so $\frac{dy}{dx}=4-x$ so $4-x=0⇒x=4$ $\frac{d^2y}{dx^2}=-1<0$ so, at $x=4$ days plant achieves max. height given by $y(4) = 4×4-\frac{4^2}{2}=8cm$ |
