Hello , how to do 6(iii)?

Step-by-step explanation:

Water is being pumped into an inflated rubber sphere at a constant rate of 0.03 cubic meters per second.

So, dV/dt = 0.03.

We want to show that dS/dt is directly proportional to 1/r.

In other words, we want to establish the relationship that dS/dt  = k(1/r), where k is some constant.

First, the volume of a sphere V is given by:

Therefore:

Next, the surface area of a sphere S is given by:

Therefore:

We can divide both sides by 2:

We can substitute this into dV/dt. Rewriting:

So:

Since dV/dt = 0.03 or 3/100:

Therefore:

Where k = 3/50.

And we have shown that dS/dt is directly proportional to 1/r.

ask the math teacher she or he would know lol.

step-by-step explanation: