 鲜花( 19)  鸡蛋( 0)
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Originally posted by gnome-kde at 2005-4-6 20:30:
1 {$ v# r: N" v; B, c2 ^% C7 v7 F这样算混淆了微分和导数的概念。1 i. r0 X- C2 V4 J
' t3 @# c6 @0 v2 L9 I4 ~; Xd(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2 n) W( G% R8 w% A( W* R) z
+ c3 }" O9 S& ^+ w( _5 mIf h(x)=(a+bx)*C(x)/x, then d(h(x))/dx = d{(a+bx)*C(x)/x}/dx = h ...
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) Y, { S. I4 l1 n" n: \) Y7 {这样算混淆了微分和导数的概念。( O0 ?/ ?( _) ^4 r
5 h3 Y% w5 d0 b0 u8 G4 r, S! hd(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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. M- i2 n; J* B b# U& b1 [Ah, you made a mistake: it should be:
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. Z* C8 d# Z0 A" A' xd(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)" q* |( ]( A9 m6 g9 g/ C. D
0 n3 B+ ], ?5 d+ i) S6 Q! cfor h(x)=(a+bx)*C(x)/x, you are right, But, no x there, it is:- ?+ H/ f5 l/ O; V
% |; R2 [6 J# I8 C. Z6 \0 yh(x)=(a+bx)*C(x) |
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