Proving Increasing Function: f'(x)=f(x) for all x

kmeado07
Messages
40
Reaction score
0

Homework Statement



Let f : R(real numbers) (arrow) (0,infinity) have the property that f ' (x) = f (x) for all x. Show that f is an increasing functions for all x.

Homework Equations





The Attempt at a Solution



I know that if f ' (x) > 0 , where all of x belongs to a,b (not bounded) then f is strictly increasing on [a,b].

So i need to show that f(x) > 0 maybe?

Any help/guidelines would be much appreciated.
 
Physics news on Phys.org
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