Solution to Continuous Function: Find x in [0,1] with f(x)=x

  • Thread starter Thread starter jmich79
  • Start date Start date
  • Tags Tags
    Functions
jmich79
Messages
10
Reaction score
0
Suppose that f is ais continuos function defined on [0,1] with f(0)=1 and f(1)=0. show that there is a value of x that in [0,1] such that f(x)=x.
I just do not understand this concept. Cna someone worjk this problem out for me and explain what's going on? Thank You.
 
Physics news on Phys.org
You take a look at f(x)-x=g(x)

g(0)=1-0=1
g(1)=0-1=-1

So on [0,1] g is continuous and goes from 1 to -1. Hence, the intermediate value theorem gives you your answer. This is like, the third thread you've made on this, and if you can't get the answer from this post, you should probably go look up the intermediate value theorem and see what it actually says
 
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