00:01
Number n of bacteria in a culture at time t is modeled with n of t equals 1000 multiplied by 30 plus e to the minus.
00:10
Now it's not very clear here but i think it says minus t over 30 so i'm just going to go along with that.
00:20
So for part a we need the initial number of bacteria so this is n of t at t equals 0, i .e.
00:28
N of 0.
00:30
When we sub in 0, we get 1000 multiplied by 30 plus e to the power of 0, which is 1.
00:38
So we get 31 times by 1000, which is 30 ,000.
00:45
Part b here, determine the rate of change in the number of bacteria at time t.
00:50
Well, this is asking what the derivative of n of t is.
00:54
So, and dash of t using the chain rule is the derivative with respect to t of, well, we know the first value is 30 ,000.
01:06
The next one is 1 ,000 e to the minus t over 30.
01:10
So we know the derivative of a constant is just 0.
01:17
And using the chain rule for 1 ,000 e to the minus t over 30, we get minus 1 ,000 over 30.
01:26
Ether minus t over 30...