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Originally posted by gnome-kde at 2005-4-6 20:30: Z7 r2 ?- L+ J4 Y% B( w: q0 Y
这样算混淆了微分和导数的概念。
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' Y, X) s" f7 ?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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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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这样算混淆了微分和导数的概念。: a5 [3 k2 H {, w0 d j- y3 G
' {' U2 @; n6 m" Q2 i" T6 t: ld(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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Ah, you made a mistake: it should be:
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5 V; R" c) j& |% v* X- Cd(f(x)g(x))/dx = f(x) d(g(x))/dx + g(x) d(f(x))/dx $ M* b# E/ t8 u0 Y4 I7 i
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' j' ` C/ I/ H) f) I& HIf 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): w- p$ n# M1 }; s9 `7 L3 b# y
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for h(x)=(a+bx)*C(x)/x, you are right, But, no x there, it is:
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5 g; G6 `7 K0 j0 y. K4 g3 c3 xh(x)=(a+bx)*C(x) |
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