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|    sci.math.symbolic    |    Symbolic algebra discussion    |    10,432 messages    |
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|    Message 9,112 of 10,432    |
|    Axel Vogt to Richard Fateman    |
|    Re: what is result of integrate(x*f(x),x    |
|    19 Jul 16 08:54:30    |
      From: //noreply@axelvogt.de              On 19.07.2016 00:50, Richard Fateman wrote:       > On 7/18/2016 11:24 AM, Axel Vogt wrote:       >> Maple's notation (D(f) = derivative of f):       >>       >> int(x*D(f)(x^2),x);       >> 2       >> 1/2 f(x )       >       > Maybe you need a better notation. What if f is       > a function of more than one variable?       >       > Conventional mathematics does       > not really provide a standard notation for       > "derivative of f with respect to its second formal argument"       > but a CAS need this, sometimes. e.g. what is       > diff(f(g(x),h(x^2)), x) ?       >       > Mathematica makes up a notation like       >       > 2 (0,1) 2       > 2 x h'[x ] f [g[x],h[x ]] + ...       >       > Maxima seems to require you to name these gradients, e.g. you could do       >       > gradef(f(u,v), f01(u,v), f10(u,v));       >       > how about Axiom, Fricas, Maple, DrHuang, etc?       > And anyone have a reputable reference to provide       > a mathematical standard?              The notation assumes f to be univariate, else one has to       provide the 'number' of the variable like              int(x*D[1](f)(x^2,y),x); # = w.r.t. the first variable               2        1/2 f(x , y)              For diff(f(g(x),h(x^2)), x) the output is using the chain       rule and displays D[1](f)( g(x),h(x^2) )*diff(g(x),x) +       2*D[2](f)( g(x),h(x^2) )*D(h)(x^2)*x , or on demand:              D[1](f)(g(x),h(x^2))*D(g)(x)+2*D[2](f)(g(x),h(x^2))*D(h)(x^2)*x              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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