# Thread: tumor and the amount of time

1. ## tumor and the amount of time

The following formula accurately models the relationship between the size of a certain type of tumor and the amount of time that it has been growing:

V(t) = 450[1 - e^(-.0017t)]^3

where t is in months and V(t) is measured in cubic centimeters. Calculate the rate of change of tumor volume at 180 months.

I think I need to differentiate the formula and substitute 180 for t.
But I don't know how to differentiate this formula because there's e and seems complicated...

2. Are you sure that's how it's written because I used this deriv. solver: calc101.com/webMathematica/derivatives.jsp and it's telling me what you typed in is zero (differentiated of course). And if it's 0, you can't plug in t for the first deriv. so that doesn't make sense..

3. Originally Posted by Pi314
Are you sure that's how it's written because I used this deriv. solver: calc101.com/webMathematica/derivatives.jsp and it's telling me what you typed in is zero (differentiated of course). And if it's 0, you can't plug in t for the first deriv. so that doesn't make sense..
Thanks you that deriv. solver really helped me. I think you miss typed in. Anyways I got the answer! Thanks again