00:01
Hi there, so for this problem, we are told that the brain mass of a fetus can be estimated using the total mass of the fetus by the function that is given.
00:10
And that function is that b is equal to 0 .22 times the mass elevated to 0 .87.
00:23
And we are given that the rate of change of b, that is the derivative of b with respect to time, equal to 0 .23 grams per day.
00:45
0 .23 grams per day.
00:55
And the other information that we are given in this case is that the value of b at this is 30.
01:08
Okay, so the value of b is 30 grams.
01:13
So what we need to obtain from this is the change of the total mass of the fetus.
01:25
So that will be the rate of change of the mass with respect to time.
01:29
So that was what we need to obtain in here.
01:31
So to obtain this expression first, we need to derive the expression for b that we are given with respect to the time.
01:39
So we will have the derivative of b with respect to time is equal to 0 .22.
01:47
We take down the exponent and that will be the mass times elevated to 0 .87 minus 1 and this times the rate of change of the mass with respect to time.
02:02
Now with that said we just need to simply solve for this for this expression right here.
02:12
So let me just use my calculator to reduce or simplify this in here.
02:24
So in here, 0 .22 times 0 .8 is equal to 0 .14.
02:51
And the other term in here is the mass elevated to.
03:01
So we will have the mass elevated to minus 0 .13...