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The rate of change of the area of a circular disc with respect to its circumference when radius is 3 is: |
6 unit 3 unit $6 \pi$ unit $2 \pi$ unit |
3 unit |
The correct answer is Option (2) - 3 unit circumference $C = 2πr$ area $a = πr^2$ $\frac{da}{dr}=2πr$ $\frac{dc}{dr}=2π⇒\frac{da}{dc}=r$ $\left.\frac{da}{dc}\right]_{r=3}=3$ unit |
