Some questions regarding a formula that's supposed to be the integral formula of Gauss and Green.

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According to my professor, this formula is called the integral formula of Gauss and Green. I've tried searching for it online but I could find nothing similar to it.



B here is a region that's bounded by the simple closed curve γ(t).



I don't really understand what is it that we get after applying this formula. I mean, when we calculate the definite integral of f over the Intervall [a,b], we get the area under the curve of f from x=a to x=b. And double integrals are used either to calculate the area of a region or the volume above it that's bounded by the surface of a multi-variable function. But what is it that we calculate using this formula?



This formula is supposed to be something slimier to the fundamental theorem of calculus but in multi-variable calculus. I cannot see how.



Thanks for all your help. And forgive me for the grammatical mistakes, if there is any. English isn't my first language.







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  • It is the green's theorem. Maybe you can notice that for a two by two matrix $A=(a|b)$ with columns $a,b$ that $det(a|b) = acdot b^perp$, where $b^perp$ Is $b$ clockwise rotated by 90 degrees
    – Calvin Khor
    Jul 24 at 22:54















up vote
0
down vote

favorite
1












According to my professor, this formula is called the integral formula of Gauss and Green. I've tried searching for it online but I could find nothing similar to it.



B here is a region that's bounded by the simple closed curve γ(t).



I don't really understand what is it that we get after applying this formula. I mean, when we calculate the definite integral of f over the Intervall [a,b], we get the area under the curve of f from x=a to x=b. And double integrals are used either to calculate the area of a region or the volume above it that's bounded by the surface of a multi-variable function. But what is it that we calculate using this formula?



This formula is supposed to be something slimier to the fundamental theorem of calculus but in multi-variable calculus. I cannot see how.



Thanks for all your help. And forgive me for the grammatical mistakes, if there is any. English isn't my first language.







share|cite|improve this question



















  • It is the green's theorem. Maybe you can notice that for a two by two matrix $A=(a|b)$ with columns $a,b$ that $det(a|b) = acdot b^perp$, where $b^perp$ Is $b$ clockwise rotated by 90 degrees
    – Calvin Khor
    Jul 24 at 22:54













up vote
0
down vote

favorite
1









up vote
0
down vote

favorite
1






1





According to my professor, this formula is called the integral formula of Gauss and Green. I've tried searching for it online but I could find nothing similar to it.



B here is a region that's bounded by the simple closed curve γ(t).



I don't really understand what is it that we get after applying this formula. I mean, when we calculate the definite integral of f over the Intervall [a,b], we get the area under the curve of f from x=a to x=b. And double integrals are used either to calculate the area of a region or the volume above it that's bounded by the surface of a multi-variable function. But what is it that we calculate using this formula?



This formula is supposed to be something slimier to the fundamental theorem of calculus but in multi-variable calculus. I cannot see how.



Thanks for all your help. And forgive me for the grammatical mistakes, if there is any. English isn't my first language.







share|cite|improve this question











According to my professor, this formula is called the integral formula of Gauss and Green. I've tried searching for it online but I could find nothing similar to it.



B here is a region that's bounded by the simple closed curve γ(t).



I don't really understand what is it that we get after applying this formula. I mean, when we calculate the definite integral of f over the Intervall [a,b], we get the area under the curve of f from x=a to x=b. And double integrals are used either to calculate the area of a region or the volume above it that's bounded by the surface of a multi-variable function. But what is it that we calculate using this formula?



This formula is supposed to be something slimier to the fundamental theorem of calculus but in multi-variable calculus. I cannot see how.



Thanks for all your help. And forgive me for the grammatical mistakes, if there is any. English isn't my first language.









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asked Jul 24 at 22:39









Ahmad Al-Mekhlafy

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  • It is the green's theorem. Maybe you can notice that for a two by two matrix $A=(a|b)$ with columns $a,b$ that $det(a|b) = acdot b^perp$, where $b^perp$ Is $b$ clockwise rotated by 90 degrees
    – Calvin Khor
    Jul 24 at 22:54

















  • It is the green's theorem. Maybe you can notice that for a two by two matrix $A=(a|b)$ with columns $a,b$ that $det(a|b) = acdot b^perp$, where $b^perp$ Is $b$ clockwise rotated by 90 degrees
    – Calvin Khor
    Jul 24 at 22:54
















It is the green's theorem. Maybe you can notice that for a two by two matrix $A=(a|b)$ with columns $a,b$ that $det(a|b) = acdot b^perp$, where $b^perp$ Is $b$ clockwise rotated by 90 degrees
– Calvin Khor
Jul 24 at 22:54





It is the green's theorem. Maybe you can notice that for a two by two matrix $A=(a|b)$ with columns $a,b$ that $det(a|b) = acdot b^perp$, where $b^perp$ Is $b$ clockwise rotated by 90 degrees
– Calvin Khor
Jul 24 at 22:54











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Rewrite the right-hand side as a line integral $$
int_a^bdetpmatrixf_1&gamma_1'\f_2&gamma_2'mathrmdt=
int_A^b f_1gamma_2'-f_2gamma_1'mathrmdt=int_partial Bf_1mathrmdy-f_2mathrmdx
$$
where $partial B$ is the positively-oriented boundary of $B,$ parameterized as $(gamma_1(t),gamma_2(t)),a leq tleq b$



Now it's somewhat reminiscent of the fundamental theorem of calculus isn't it? On the right hand side, we're integrating some function over the boundary. On the left-hand side we're integrating some kind of derivative of that function over the whole area.



This idea can be made precise and generalized to any number of dimensions and in other ways, but that takes a lot of work.



Integrals have many more interpretations and uses than simply areas or volumes. If they didn't, they wouldn't be nearly as important as they are.






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    Rewrite the right-hand side as a line integral $$
    int_a^bdetpmatrixf_1&gamma_1'\f_2&gamma_2'mathrmdt=
    int_A^b f_1gamma_2'-f_2gamma_1'mathrmdt=int_partial Bf_1mathrmdy-f_2mathrmdx
    $$
    where $partial B$ is the positively-oriented boundary of $B,$ parameterized as $(gamma_1(t),gamma_2(t)),a leq tleq b$



    Now it's somewhat reminiscent of the fundamental theorem of calculus isn't it? On the right hand side, we're integrating some function over the boundary. On the left-hand side we're integrating some kind of derivative of that function over the whole area.



    This idea can be made precise and generalized to any number of dimensions and in other ways, but that takes a lot of work.



    Integrals have many more interpretations and uses than simply areas or volumes. If they didn't, they wouldn't be nearly as important as they are.






    share|cite|improve this answer

























      up vote
      0
      down vote













      Rewrite the right-hand side as a line integral $$
      int_a^bdetpmatrixf_1&gamma_1'\f_2&gamma_2'mathrmdt=
      int_A^b f_1gamma_2'-f_2gamma_1'mathrmdt=int_partial Bf_1mathrmdy-f_2mathrmdx
      $$
      where $partial B$ is the positively-oriented boundary of $B,$ parameterized as $(gamma_1(t),gamma_2(t)),a leq tleq b$



      Now it's somewhat reminiscent of the fundamental theorem of calculus isn't it? On the right hand side, we're integrating some function over the boundary. On the left-hand side we're integrating some kind of derivative of that function over the whole area.



      This idea can be made precise and generalized to any number of dimensions and in other ways, but that takes a lot of work.



      Integrals have many more interpretations and uses than simply areas or volumes. If they didn't, they wouldn't be nearly as important as they are.






      share|cite|improve this answer























        up vote
        0
        down vote










        up vote
        0
        down vote









        Rewrite the right-hand side as a line integral $$
        int_a^bdetpmatrixf_1&gamma_1'\f_2&gamma_2'mathrmdt=
        int_A^b f_1gamma_2'-f_2gamma_1'mathrmdt=int_partial Bf_1mathrmdy-f_2mathrmdx
        $$
        where $partial B$ is the positively-oriented boundary of $B,$ parameterized as $(gamma_1(t),gamma_2(t)),a leq tleq b$



        Now it's somewhat reminiscent of the fundamental theorem of calculus isn't it? On the right hand side, we're integrating some function over the boundary. On the left-hand side we're integrating some kind of derivative of that function over the whole area.



        This idea can be made precise and generalized to any number of dimensions and in other ways, but that takes a lot of work.



        Integrals have many more interpretations and uses than simply areas or volumes. If they didn't, they wouldn't be nearly as important as they are.






        share|cite|improve this answer













        Rewrite the right-hand side as a line integral $$
        int_a^bdetpmatrixf_1&gamma_1'\f_2&gamma_2'mathrmdt=
        int_A^b f_1gamma_2'-f_2gamma_1'mathrmdt=int_partial Bf_1mathrmdy-f_2mathrmdx
        $$
        where $partial B$ is the positively-oriented boundary of $B,$ parameterized as $(gamma_1(t),gamma_2(t)),a leq tleq b$



        Now it's somewhat reminiscent of the fundamental theorem of calculus isn't it? On the right hand side, we're integrating some function over the boundary. On the left-hand side we're integrating some kind of derivative of that function over the whole area.



        This idea can be made precise and generalized to any number of dimensions and in other ways, but that takes a lot of work.



        Integrals have many more interpretations and uses than simply areas or volumes. If they didn't, they wouldn't be nearly as important as they are.







        share|cite|improve this answer













        share|cite|improve this answer



        share|cite|improve this answer











        answered Jul 24 at 23:37









        saulspatz

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