A circle with radius 5cm has its radius increasing at the...
A circle with radius 5cm has its radius increasing at the rate of 0.2m/s. What will be the corresponding increase in the area?
2π
5π
π
4π
Correct answer is A
Area of the circle (A) = \(\pi r^{2}\)
\(\frac{\mathrm d A}{\mathrm d r} = 2\pi r\)
\(\frac{\mathrm d A}{\mathrm d t} = \frac{\mathrm d A}{\mathrm d r} . \frac{\mathrm d r}{\mathrm d t}\)
\(\frac{\mathrm d A}{\mathrm d t} = 2\pi \times 5 \times 0.2 = 2\pi\)
P(-6, 1) and Q(6, 6) are the two ends of the diameter of a given circle. Calculate the radius. ...
Find the equation of the tangent at the point (2, 0) to the curve y = x\(^2\) - 2x...
In the figure, STQ = SRP, PT = TQ = 6cm and QS = 5cm. Find SR ...
If m * n = n - (m+2) for any real number m and n find the value of 3*(-5)? ...
What is log7(49a) - log10(0.01)?...
Find the value of x for which \(\frac{x - 5}{x(x - 1)}\) is defined...