Differentiation question with continuity

inter060708
Messages
24
Reaction score
0

Homework Statement



Suppose a function f is continuous and has continuous derivatives of all orders for all
x. it satisfies xf ''(x) + f '(x) + xf(x) = 0. Given f(0) = 1

find the value of f '(0) and f '' (0).

Homework Equations


The Attempt at a Solution



when x=0,

0f''(0) + f ' (0) + 0f(0) = 0
therefore f ' (0) = 0

Now, I am not sure on how to find f ''(0). Is it undefined?
Thanks for your help.
 
Last edited:
Physics news on Phys.org
There's no attempt at a solution. You have to make one. Then you can get some help.
 
I have added the solution attempt, please help. Thanks :)
 
That helps. Try differentiating xf ''(x) + f '(x) + xf(x) = 0 and putting x=0 again.
 
Wow. Thanks Dick! :D
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top