Question

The radius of a circle is increasing at the rate of 0.7 cm/s. What is the rate of
increase of its circumference?

Answer 1

@terenzreignz

Answer 2

\[\huge C = 2\pi r\]\[\huge \frac{dC}{dr}=2\pi\]

Answer 3

\[\frac{ dr }{ dt }=0.7 \ cm/s\]\[C=2 \pi r\]\[\frac{ dC }{ dt }=2 \pi\]\[\bf \frac{ dC }{ dr }=\frac{ \frac{ dC }{ dt } }{ \frac{ dr }{ dt } }\]

@goformit100

Answer 4

Plug everything in again and solve.

Answer 5

\[\large \frac{dC}{dt} =_{?} 2\pi \]
@genius12
I dispute this...

Answer 6

Thank you Sir

Answer 7

Sorry @terenzreignz

I forgot to include the dr/dt in dC/dt lol.

Answer 8

@goformit100 \[\frac{ dC }{ dt }=2\pi \frac{ dr }{ dt }\] Please make this correction.

Answer 9

Thanks @genius12