Let V be the vector space of continuous functions from R to R. Let T be the linear operator on V defined as (Tf)(x)=∫x0f(t)dt
Prove that T doesn't have eigenvalues.
I want to show that it doesn't exist any continuous function f≠0 with (1) ∫x0f(t)dt=λf(x), for some λ and for all x∈R
So suppose it does, then λf(0)=∫00f(t)dt=0, from here it follows f(0)=0. From equation (1) we also arrive to the inequality λ|f(x)|≤|x|max|f(t)|
where max|f(t)| is the maximum the function attains on the [0,x] or [x,0] respectively.
I would like to arrive to an absurd but I couldn't, any hints or suggestions would be greatly appreciated.
Answer
It follows from your equation (1) that f is differentiable and
f(x)=λf′(x) for all x∈R. The general solution of
this differential equation is f(x)=Cexp(x/λ) for some C∈R.
Since f(0)=0, f is identically zero.
No comments:
Post a Comment