…. At what rate is the perimeter changing when the side is 10cm long?
I am not very good at these related rate questions so if anyone could help me through it that would be great.
From what i know and if i am correct, this is what i have so far..
ds/dt = 5
A = s^2
Let A be area in cm, Let s be the length of the side, Let t be the time in seconds
So we are looking for dA/dt when s = 10? If i am correct?
If so then would this be the formula?
dA/dt = d/dt (s^2) = 2s(ds/dt)?
Now i am a little confused.
Best Answer
$$A=s^2\implies {dA\over dt}={d\over dt}(s^2)=2s{ds\over dt}=2\times 10\times 5=100$$