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Originally posted by gnome-kde at 2005-4-6 20:30:
+ b) s4 r- l& c: U2 K这样算混淆了微分和导数的概念。- l$ p/ P) Q+ G b3 F
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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) H& V5 f3 F* D% ^- z8 }0 Y% @% j
( Q/ D3 Q9 x! Z, l) ?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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9 f' \$ C# [ H. C7 L2 p/ f这样算混淆了微分和导数的概念。
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( ]1 T, Y+ B- v* n) qd(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- d: d+ Z* G5 @0 W& l' Q6 v
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Ah, you made a mistake: it should be:1 R' ?; C# _: E6 Y+ ~" A
* L; v8 E5 D6 vd(f(x)g(x))/dx = f(x) d(g(x))/dx + g(x) d(f(x))/dx
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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'(x) = [xb*c(x)+x(a+bx)*c'(x)-(a+bx)*c(x)]/x2 (应该对吧, 我也没验算)8 e0 P6 I6 p2 O( Y2 I. l1 L
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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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1 y5 X( ^4 w, J( A/ }$ v: Jh(x)=(a+bx)*C(x) |
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