Qn : Does a continuous function always have a fixed point in [0, 1]?

ice_kid
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I hope someone can help me wif this qnestion.

Qn : Let f ; g be continuous functions from [0, 1] onto [0, 1]. Prove that there is
x0 ∈ [0, 1] such that f (g(x0)) = g(f (x0)).

Thanks in advance.
 
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ice_kid said:
I hope someone can help me wif this qnestion.

Qn : Let f ; g be continuous functions from [0, 1] onto [0, 1]. Prove that there is
x0 ∈ [0, 1] such that f (g(x0)) = g(f (x0)).

Thanks in advance.

Since both functions are onto [0,1], there are points a and b in [0,1] such that f(g(a)) = 0 and f(g(b)) = 1.

Then we must have
f(g(a)) - g(f(a)) \leq 0
and
f(g(b)) - g(f(b)) \geq 0.

The function h defined by h(x) = f(g(x)) - g(f(x)) is continuous. So...

Maybe you can take it from here.
 
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