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The edge of a cube is decreasing at the rate ofcm0.6cmsec. Find the rate at which its volume is decreasing, when the edge of the cube is 2 cm.

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प्रश्न

The edge of a cube is decreasing at the rate of`( 0.6"cm")/sec`. Find the rate at which its volume is decreasing, when the edge of the cube is 2 cm.

योग
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उत्तर

Let x be the edge of the cube and V be its volume at any time t.
Then V = x3
Differentiating both sides w.r.t. t, we get

`"dV"/"dt" = 3x^2"dx"/"dt"`

Now, `dx/dt = (0.6"cm")/sec` and x = 2 cm

∴ `"dV"/dt` = 3(2)2(0.6)

= 7.2
Hence, the volume of the cube is decreasing at the rate of `(7.2"cm"^3)/sec`.

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अध्याय 2: Applications of Derivatives - Exercise 2.1 [पृष्ठ ७२]

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बालभारती Mathematics and Statistics 2 (Arts and Science) [English] Standard 12 Maharashtra State Board
अध्याय 2 Applications of Derivatives
Exercise 2.1 | Q 12 | पृष्ठ ७२

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