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Originally posted by gnome-kde at 2005-4-6 20:30:4 W9 |# L- S; q
这样算混淆了微分和导数的概念。
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d(f(x))/dx = f'(x), d(f(x)g(x))/dx = f'(x) d(g(x))/dx + g'(x) d(f(x))/dx 这是基本的微分四则运算
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( S# }& a' H0 T; ]( RIf h(x)=(a+bx)*C(x)/x, then d(h(x))/dx = d{(a+bx)*C(x)/x}/dx = h ...
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) b8 N; S2 W/ ?& A: C& Y这样算混淆了微分和导数的概念。8 h+ g$ ~! I0 x, o% l* \' M0 H
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d(f(x))/dx = f'(x), d(f(x)g(x))/dx = f'(x) d(g(x))/dx + g'(x) d(f(x))/dx 这是基本的微分四则运算
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& }6 M% D8 u b! i. L/ ^Ah, you made a mistake: it should be:
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' P9 G6 ^" }5 c. o2 N* [d(f(x)g(x))/dx = f(x) d(g(x))/dx + g(x) d(f(x))/dx 1 N% k- M1 f' c8 o( V- {
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$ @3 W& b/ ~5 O. }2 |& OIf h(x)=(a+bx)*C(x)/x, then d(h(x))/dx = d{(a+bx)*C(x)/x}/dx = h'(x) = [xb*c(x)+x(a+bx)*c'(x)-(a+bx)*c(x)]/x2 (应该对吧, 我也没验算)$ x- T$ Z V, l
' `5 x7 H/ q l+ j+ Y* }, afor h(x)=(a+bx)*C(x)/x, you are right, But, no x there, it is:
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$ Q. W- A3 U& ]) K. L- T ]( sh(x)=(a+bx)*C(x) |
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