Finite element method for the construction of the approximation of the solution

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SUMMARY

The discussion focuses on applying the finite element method (FEM) to solve a specific two-point boundary value problem defined by the differential equation $$-y''(x)+(by)'(x)=f(x)$$ with boundary conditions $y(0)=0$ and $y'(1)=my(1)$. The proposed approach involves constructing an approximation of the solution $y$ using a finite element space $S$ consisting of continuous and partially linear functions. The user seeks validation of their method, which includes integrating by parts and applying boundary conditions to derive the weak form of the problem.

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mathmari
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Hey! :o

Given the following two-point problem:
$$-y''(x)+(by)'(x)=f(x), \forall x \in [0,1]$$
$$y(0)=0, y'(1)=my(1)$$
where $ b \in C^1([0,1];R), f \in C([0,1];R)$ and $ m \in R$ a constant.
Give a finite element method for the construction of the approximation of the solution $y$ of the problem above, where the finite element space ($S$) consists of continuous and partially linear functions.

My idea is the following:
$ u \in S:$
$$ -\int_0^1{u''g}dx+ \int_0^1{bu'g}dx= \int_0^1{fg}dx$$
$$ -u'g|_0^1+ \int_0^1{u'g'}dx+ \int_0^1{bu'g}dx= \int_0^1{fg}dx$$
$$-mu(1)+g(1)+ \int_0^1{u'g'}dx+ \int_0^1{bu'g}dx= \int_0^1{fg}dx$$
$ \forall g \in S$

Could you tell me if this is correct?
 
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To find the method we take a function $g$ of $S$, right? Does this function satisfy the conditions of the problem? I mean $g(0)=0, g'(1)=mg(1)$... Or is there an other way to find the method?
 

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