Show integrable is uniformly continuous

  • Thread starter Thread starter HF08
  • Start date Start date
  • Tags Tags
    Continuous
HF08
Messages
39
Reaction score
0
H = [a,b]\times[c,d] . f:H\rightarrowR is continuous, and
g:[a,b]\rightarrowR is integrable.

Prove that
F(y) = \intg(x)f(x,y)dx from a to b is uniformly continuous.


I initially ripped g(x) and f(x,y) apart and tried to show each was continuous. This failed.
In short, I am completely stuck. Please help me.
 
Physics news on Phys.org
g(x) is only given as integrable, not necessarily continuous so that couldn't work.
 
Hint: since H is compact, f is, in fact, uniformly continuous. Use that to show for all epsilon>0, there exists a delta>0 such that |f(x,y0)-f(x,y)|<delta for all y such that |y-y0|<delta (for all x). Use that to show that the integral F(y) is continuous at y0. Once you know it's continuous, you don't have to worry about the uniform part, since y is in [c,d], which is also compact.
 
Back
Top