Finding a C1 Function for Continuous f,g in Real Numbers

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The discussion revolves around finding a C^1 function h defined on R^2 excluding the origin, which matches given C^1 functions r and s on specific sets A and B defined by continuous functions f and g. The user initially expresses uncertainty about how to approach the problem, suggesting a connection to partitions of unity. However, they later update the thread to indicate that the problem has been solved. The conversation highlights the importance of continuity and differentiability in constructing the desired function. Overall, the thread illustrates a successful resolution to a mathematical challenge involving continuous functions.
johnson12
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Hello,I need some advice on a problem.

Let f,g:R\rightarrow R (where R denotes the real numbers) be two continuous functions, assume that f(x) < g(x) \forall x \neq 0 ,

and f(0) = g(0).Define A = \left\{(x,y)\neq (0,0): y&lt; f(x),x \in R\right\}<br />

B = \left\{(x,y)\neq (0,0): y&gt; g(x),x \in R\right\}<br />Let r,s:R^{2}\rightarrow R be C^{1},and show that there is a C^{1} function h defined on

R^{2}- \left\{(0,0)\right\} such that h(x,y) = r(x,y) on A and h(x,y) = s(x,y) on B.

It seems that this follows from partitions of unity, but I am not sure where to
start, any suggestions at all are helpful.
Thanks.
 
Last edited:
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johnson12 said:
Hello,I need some advice on a problem.

Let f,g:R\rightarrow R (where R denotes the real numbers) be two continuous functions, assume that f(x) &lt; g(x) \forall x \neq 0 ,

and f(0) = g(0).Define A = \left\{(x,y)\neq (0,0): y&lt; f(x),x \in R\right\}<br />

B = \left\{(x,y)\neq (0,0): y&gt; g(x),x \in R\right\}<br />


Let r,s:R^{2}\rightarrow R be C^{1},and show that there is a C^{1} function h defined on

R^{2}- \left\{(0,0)\right\} such that h(x,y) = r(x,y) on A and h(x,y) = s(x,y) on B.

It seems that this follows from partitions of unity, but I am not sure where to
start, any suggestions at all are helpful.
Thanks.

UPDATE: PROBLEM SOLVED
 

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