Question:
If a circular plate is heated uniformly, its area expands 3c times as fast as its radius, then the value of c when the radius is 6 units, is
If a circular plate is heated uniformly, its area expands 3c times as fast as its radius, then the value of c when the radius is 6 units, is
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Always relate rates using differentiation.
Updated On: Mar 18, 2026
- 4π
- 2π
- 6π
- 3π
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The Correct Option is B
Solution and Explanation
Step 1: Area of circle A=π r²
Step 2: Differentiate w.r.t. time: (dA)/(dt)=2π r(dr)/(dt)
Step 3: Given (dA)/(dt)=3c(dr)/(dt) 2π r=3c c=(2π r)/(3)
Step 4: For r=6, c=2π
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