Integral d notation












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Is the following notation somehow wrong (or rather can it produce wrong results)?
$$int{f'(x)dx} = int{df(x)} = f(x) + C$$
As far as I know this is pretty standard notation in many Russian textbooks. But I was made aware that this is not the case in western countries, and some people I talked with still believe it is wrong even after I explained it. Is there a reason to believe that this may produce wrong results? As far as I can tell it's simply $frac{df}{dx} dx = df$. Relevant to this: wikipedia










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  • 1




    $begingroup$
    It certainly makes sense if $f$ is $C^1$, either as integral of differential forms or as Riemann-Stieltjes integral.
    $endgroup$
    – Sangchul Lee
    Jan 20 at 19:59






  • 1




    $begingroup$
    It doesn't matter whether you view $intdots dx$ as the anti-derivative symbol of the integrand $f$ or you view $int$ alone as the anti-differential symbol of $f ;dx$. This is because derivatives and differentials are essentially two ways of doing the exact same thing. Therefore, since this operations are essentially the same, they will have essentially the same inverse operation. You can view $int$ as an anti-derivative symbol of the integrand or you can view $int$ as the anti-differential symbol of the integrand + dx. It doesn't matter because derivatives and differentials are similar
    $endgroup$
    – DWade64
    Jan 20 at 20:24






  • 1




    $begingroup$
    If $F$ is an anti-derivative of $f$, then $F = int f dx$, but $dF$ is also $dF = f dx$, so $int$ can also mean anti-differential of $f; dx$ in my opinion. Derivatives and differentials are basically the same thing, which is why you can write 1st order differential equations with derivatives or differentials, either or. So I think you are right
    $endgroup$
    – DWade64
    Jan 20 at 20:26


















2












$begingroup$


Is the following notation somehow wrong (or rather can it produce wrong results)?
$$int{f'(x)dx} = int{df(x)} = f(x) + C$$
As far as I know this is pretty standard notation in many Russian textbooks. But I was made aware that this is not the case in western countries, and some people I talked with still believe it is wrong even after I explained it. Is there a reason to believe that this may produce wrong results? As far as I can tell it's simply $frac{df}{dx} dx = df$. Relevant to this: wikipedia










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    It certainly makes sense if $f$ is $C^1$, either as integral of differential forms or as Riemann-Stieltjes integral.
    $endgroup$
    – Sangchul Lee
    Jan 20 at 19:59






  • 1




    $begingroup$
    It doesn't matter whether you view $intdots dx$ as the anti-derivative symbol of the integrand $f$ or you view $int$ alone as the anti-differential symbol of $f ;dx$. This is because derivatives and differentials are essentially two ways of doing the exact same thing. Therefore, since this operations are essentially the same, they will have essentially the same inverse operation. You can view $int$ as an anti-derivative symbol of the integrand or you can view $int$ as the anti-differential symbol of the integrand + dx. It doesn't matter because derivatives and differentials are similar
    $endgroup$
    – DWade64
    Jan 20 at 20:24






  • 1




    $begingroup$
    If $F$ is an anti-derivative of $f$, then $F = int f dx$, but $dF$ is also $dF = f dx$, so $int$ can also mean anti-differential of $f; dx$ in my opinion. Derivatives and differentials are basically the same thing, which is why you can write 1st order differential equations with derivatives or differentials, either or. So I think you are right
    $endgroup$
    – DWade64
    Jan 20 at 20:26
















2












2








2


2



$begingroup$


Is the following notation somehow wrong (or rather can it produce wrong results)?
$$int{f'(x)dx} = int{df(x)} = f(x) + C$$
As far as I know this is pretty standard notation in many Russian textbooks. But I was made aware that this is not the case in western countries, and some people I talked with still believe it is wrong even after I explained it. Is there a reason to believe that this may produce wrong results? As far as I can tell it's simply $frac{df}{dx} dx = df$. Relevant to this: wikipedia










share|cite|improve this question









$endgroup$




Is the following notation somehow wrong (or rather can it produce wrong results)?
$$int{f'(x)dx} = int{df(x)} = f(x) + C$$
As far as I know this is pretty standard notation in many Russian textbooks. But I was made aware that this is not the case in western countries, and some people I talked with still believe it is wrong even after I explained it. Is there a reason to believe that this may produce wrong results? As far as I can tell it's simply $frac{df}{dx} dx = df$. Relevant to this: wikipedia







calculus integration notation






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share|cite|improve this question











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asked Jan 20 at 19:48









lightxbulblightxbulb

925311




925311








  • 1




    $begingroup$
    It certainly makes sense if $f$ is $C^1$, either as integral of differential forms or as Riemann-Stieltjes integral.
    $endgroup$
    – Sangchul Lee
    Jan 20 at 19:59






  • 1




    $begingroup$
    It doesn't matter whether you view $intdots dx$ as the anti-derivative symbol of the integrand $f$ or you view $int$ alone as the anti-differential symbol of $f ;dx$. This is because derivatives and differentials are essentially two ways of doing the exact same thing. Therefore, since this operations are essentially the same, they will have essentially the same inverse operation. You can view $int$ as an anti-derivative symbol of the integrand or you can view $int$ as the anti-differential symbol of the integrand + dx. It doesn't matter because derivatives and differentials are similar
    $endgroup$
    – DWade64
    Jan 20 at 20:24






  • 1




    $begingroup$
    If $F$ is an anti-derivative of $f$, then $F = int f dx$, but $dF$ is also $dF = f dx$, so $int$ can also mean anti-differential of $f; dx$ in my opinion. Derivatives and differentials are basically the same thing, which is why you can write 1st order differential equations with derivatives or differentials, either or. So I think you are right
    $endgroup$
    – DWade64
    Jan 20 at 20:26
















  • 1




    $begingroup$
    It certainly makes sense if $f$ is $C^1$, either as integral of differential forms or as Riemann-Stieltjes integral.
    $endgroup$
    – Sangchul Lee
    Jan 20 at 19:59






  • 1




    $begingroup$
    It doesn't matter whether you view $intdots dx$ as the anti-derivative symbol of the integrand $f$ or you view $int$ alone as the anti-differential symbol of $f ;dx$. This is because derivatives and differentials are essentially two ways of doing the exact same thing. Therefore, since this operations are essentially the same, they will have essentially the same inverse operation. You can view $int$ as an anti-derivative symbol of the integrand or you can view $int$ as the anti-differential symbol of the integrand + dx. It doesn't matter because derivatives and differentials are similar
    $endgroup$
    – DWade64
    Jan 20 at 20:24






  • 1




    $begingroup$
    If $F$ is an anti-derivative of $f$, then $F = int f dx$, but $dF$ is also $dF = f dx$, so $int$ can also mean anti-differential of $f; dx$ in my opinion. Derivatives and differentials are basically the same thing, which is why you can write 1st order differential equations with derivatives or differentials, either or. So I think you are right
    $endgroup$
    – DWade64
    Jan 20 at 20:26










1




1




$begingroup$
It certainly makes sense if $f$ is $C^1$, either as integral of differential forms or as Riemann-Stieltjes integral.
$endgroup$
– Sangchul Lee
Jan 20 at 19:59




$begingroup$
It certainly makes sense if $f$ is $C^1$, either as integral of differential forms or as Riemann-Stieltjes integral.
$endgroup$
– Sangchul Lee
Jan 20 at 19:59




1




1




$begingroup$
It doesn't matter whether you view $intdots dx$ as the anti-derivative symbol of the integrand $f$ or you view $int$ alone as the anti-differential symbol of $f ;dx$. This is because derivatives and differentials are essentially two ways of doing the exact same thing. Therefore, since this operations are essentially the same, they will have essentially the same inverse operation. You can view $int$ as an anti-derivative symbol of the integrand or you can view $int$ as the anti-differential symbol of the integrand + dx. It doesn't matter because derivatives and differentials are similar
$endgroup$
– DWade64
Jan 20 at 20:24




$begingroup$
It doesn't matter whether you view $intdots dx$ as the anti-derivative symbol of the integrand $f$ or you view $int$ alone as the anti-differential symbol of $f ;dx$. This is because derivatives and differentials are essentially two ways of doing the exact same thing. Therefore, since this operations are essentially the same, they will have essentially the same inverse operation. You can view $int$ as an anti-derivative symbol of the integrand or you can view $int$ as the anti-differential symbol of the integrand + dx. It doesn't matter because derivatives and differentials are similar
$endgroup$
– DWade64
Jan 20 at 20:24




1




1




$begingroup$
If $F$ is an anti-derivative of $f$, then $F = int f dx$, but $dF$ is also $dF = f dx$, so $int$ can also mean anti-differential of $f; dx$ in my opinion. Derivatives and differentials are basically the same thing, which is why you can write 1st order differential equations with derivatives or differentials, either or. So I think you are right
$endgroup$
– DWade64
Jan 20 at 20:26






$begingroup$
If $F$ is an anti-derivative of $f$, then $F = int f dx$, but $dF$ is also $dF = f dx$, so $int$ can also mean anti-differential of $f; dx$ in my opinion. Derivatives and differentials are basically the same thing, which is why you can write 1st order differential equations with derivatives or differentials, either or. So I think you are right
$endgroup$
– DWade64
Jan 20 at 20:26












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Said people found an explanation: https://en.wikipedia.org/wiki/Riemann%E2%80%93Stieltjes_integral






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    $begingroup$

    Said people found an explanation: https://en.wikipedia.org/wiki/Riemann%E2%80%93Stieltjes_integral






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      Said people found an explanation: https://en.wikipedia.org/wiki/Riemann%E2%80%93Stieltjes_integral






      share|cite|improve this answer









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        $begingroup$

        Said people found an explanation: https://en.wikipedia.org/wiki/Riemann%E2%80%93Stieltjes_integral






        share|cite|improve this answer









        $endgroup$



        Said people found an explanation: https://en.wikipedia.org/wiki/Riemann%E2%80%93Stieltjes_integral







        share|cite|improve this answer












        share|cite|improve this answer



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        answered Jan 20 at 19:59









        lightxbulblightxbulb

        925311




        925311






























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