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Originally posted by gnome-kde at 2005-4-6 20:30:) p/ J# i6 k i+ X
这样算混淆了微分和导数的概念。: j" X- o. ~9 w3 E* ]# n: B. k& i
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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 ], Q/ l, B, J, w$ y+ a. K
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If h(x)=(a+bx)*C(x)/x, then d(h(x))/dx = d{(a+bx)*C(x)/x}/dx = h ...
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) v' v$ Z7 O; f$ v1 M; M这样算混淆了微分和导数的概念。' I. k% |' V4 F @" E3 \% h; e
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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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0 V; j6 g2 N: m# ?Ah, you made a mistake: it should be:
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9 z: J& B9 m: e3 t! h" b" Kd(f(x)g(x))/dx = f(x) d(g(x))/dx + g(x) d(f(x))/dx 6 p2 k5 n* g( `, E {7 W! a' [
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+ F3 `3 M) _- _+ mIf 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) M/ t( m4 x, D/ t: M. Q* a
# m6 M. L' a+ P9 ?. O6 K- C, jfor h(x)=(a+bx)*C(x)/x, you are right, But, no x there, it is:* B( d% i, _9 L4 x" G! o) W
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h(x)=(a+bx)*C(x) |
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