- #1
Sisyphus
- 62
- 0
Hello Calculus Forum,
I need some help in differentiating piecewise functions and finding local/absolute minimum/maximum values. Problem is, I don't know how. For example, ...-x , if x<0
f(x)={ 2x^3-15x^2+36x , if 0<x<4, or x=0, or x=4
... 216-x , if x>4my first inclination is to differentiate each part separately, see where the slopes change in each part, and then calculuate the min/max values using the critical points, but I am not arriving at the correct answers. =\
I can find out the critical points of the middle part pretty easily
(x= 2,x=3), but my answer key also reads that there is a local minimum point at f(0)=0
I really don't have a good idea of how f(0) could be a minimum value, unless it is because x=0 is where the first part of the fuction ends and where the second piece begins, but if I am right in that regard, why isn't x=4 also considered a critical value?
Hope my question makes sense, and so on.
...
I need some help in differentiating piecewise functions and finding local/absolute minimum/maximum values. Problem is, I don't know how. For example, ...-x , if x<0
f(x)={ 2x^3-15x^2+36x , if 0<x<4, or x=0, or x=4
... 216-x , if x>4my first inclination is to differentiate each part separately, see where the slopes change in each part, and then calculuate the min/max values using the critical points, but I am not arriving at the correct answers. =\
I can find out the critical points of the middle part pretty easily
(x= 2,x=3), but my answer key also reads that there is a local minimum point at f(0)=0
I really don't have a good idea of how f(0) could be a minimum value, unless it is because x=0 is where the first part of the fuction ends and where the second piece begins, but if I am right in that regard, why isn't x=4 also considered a critical value?
Hope my question makes sense, and so on.
...