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mzd418835233 · 2011-04-03, 17:15

这个式子求A对g的一阶导数，

syms v g f
y=(((2.*v.*g).^2+(g.^2-f.^2).^2)./((2.*v.*g).^2.*(g.^2-1+v.*g.^2).^2+(v.*f.^2.*g.^2-(g.^2-1).*(g.^2-f.^2)).^2)).^0.5;
diff(y,g)

小弟的结果

ans =

1/2/((4*v^2*g^2+(g^2-f^2)^2)/(4*v^2*g^2*(g^2-1+v*g^2)^2+(v*f^2*g^2-(g^2-1)*(g^2-f^2))^2))^(1/2)*((8*v^2*g+4*(g^2-f^2)*g)/(4*v^2*g^2*(g^2-1+v*g^2)^2+(v*f^2*g^2-(g^2-1)*(g^2-f^2))^2)-(4*v^2*g^2+(g^2-f^2)^2)/(4*v^2*g^2*(g^2-1+v*g^2)^2+(v*f^2*g^2-(g^2-1)*(g^2-f^2))^2)^2*(8*v^2*g*(g^2-1+v*g^2)^2+8*v^2*g^2*(g^2-1+v*g^2)*(2*g+2*v*g)+2*(v*f^2*g^2-(g^2-1)*(g^2-f^2))*(2*v*f^2*g-2*(g^2-f^2)*g-2*(g^2-1)*g)))

能弄成我们常用的分式吗？求高手啊！！！！

2011-04-03, 17:15	#1
mzd418835233 初级会员注册日期: 2011-04-03 年龄: 35 帖子: 2 声望力: 0	菜鸟跪求高手帮忙先谢谢！这个式子求A对g的一阶导数， syms v g f y=(((2.v.g).^2+(g.^2-f.^2).^2)./((2.v.g).^2.(g.^2-1+v.g.^2).^2+(v.f.^2.g.^2-(g.^2-1).(g.^2-f.^2)).^2)).^0.5; diff(y,g) 小弟的结果 ans = 1/2/((4v^2g^2+(g^2-f^2)^2)/(4v^2g^2(g^2-1+vg^2)^2+(vf^2g^2-(g^2-1)(g^2-f^2))^2))^(1/2)((8v^2g+4(g^2-f^2)g)/(4v^2g^2(g^2-1+vg^2)^2+(vf^2g^2-(g^2-1)(g^2-f^2))^2)-(4v^2g^2+(g^2-f^2)^2)/(4v^2g^2(g^2-1+vg^2)^2+(vf^2g^2-(g^2-1)(g^2-f^2))^2)^2(8v^2g(g^2-1+vg^2)^2+8v^2g^2(g^2-1+vg^2)(2g+2vg)+2(vf^2g^2-(g^2-1)(g^2-f^2))(2vf^2g-2(g^2-f^2)g-2(g^2-1)g))) 能弄成我们常用的分式吗？求高手啊！！！！