 鲜花( 19)  鸡蛋( 0)
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Originally posted by gnome-kde at 2005-4-6 20:30:8 E9 {) ?/ r% [7 z; c8 n
这样算混淆了微分和导数的概念。% i y6 r) i2 h0 A0 m; L" e0 ^$ K4 |
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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! r0 [! I, S) C5 g6 r9 W' k: y: g
( P: N; V0 Z# @# P; U3 v# hIf 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。5 n0 ^9 [# z! b8 `' O
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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6 y4 y5 |9 F1 J
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Ah, you made a mistake: it should be: ^9 c; M! T+ x- v
- u8 f* X8 }) a" I8 M& fd(f(x)g(x))/dx = f(x) d(g(x))/dx + g(x) d(f(x))/dx
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6 l; R( ?. o) 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)9 N# r+ Y4 p3 L8 Y, ~& _9 @
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for h(x)=(a+bx)*C(x)/x, you are right, But, no x there, it is:* {; C0 r& f% M8 }9 P. a! y6 E2 R/ I
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h(x)=(a+bx)*C(x) |
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