Question

matlab 解方程问题，solve解不出来

syms COHadd Cblg N1 N2 N3 N4 N5 N6 N7 Kb COH0 COH
solve('(COHadd - COH)/Cblg = N1*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) + N2*(1/(1+Kb*COH0) - 1/(1 + Kb*COH))+ N3*(1/(1 + Kb*COH0)-1/(1 + Kb*COH)) + N4*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) + N5*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) + N6*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) + N7*(1/(1+Kb*COH0) - 1/(1+Kb*COH))','COH')
总报错，哪位高手帮忙解决一下，谢谢

Answer 1

确实没有错，我的MATLAB是2012B

syms COHadd Cblg N1 N2 N3 N4 N5 N6 N7 Kb COH0 COH real

solve('(COHadd - COH)/Cblg = N1*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) + N2*(1/(1+Kb*COH0) - 1/(1 + Kb*COH))+ N3*(1/(1 + Kb*COH0)-1/(1 + Kb*COH)) + N4*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) + N5*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) + N6*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) + N7*(1/(1+Kb*COH0) - 1/(1+Kb*COH))','COH')

simple(ans)

有两个解

追问

不好意思啊，只能采纳一个答案，好像是我的matlab版本有点低

Answer 2

没有报错啊，结果是：
ans =

-((COH0^2*COHadd^2*Kb^4 + 2*COH0^2*COHadd*Kb^3 + 4*COH0^2*Cblg*Kb^3*N1 + 4*COH0^2*Cblg*Kb^3*N2 + 4*COH0^2*Cblg*Kb^3*N3 + 4*COH0^2*Cblg*Kb^3*N4 + 4*COH0^2*Cblg*Kb^3*N5 + 4*COH0^2*Cblg*Kb^3*N6 + 4*COH0^2*Cblg*Kb^3*N7 + COH0^2*Kb^2 + 2*COH0*COHadd^2*Kb^3 - 2*COH0*COHadd*Cblg*Kb^3*N1 - 2*COH0*COHadd*Cblg*Kb^3*N2 - 2*COH0*COHadd*Cblg*Kb^3*N3 - 2*COH0*COHadd*Cblg*Kb^3*N4 - 2*COH0*COHadd*Cblg*Kb^3*N5 - 2*COH0*COHadd*Cblg*Kb^3*N6 - 2*COH0*COHadd*Cblg*Kb^3*N7 + 4*COH0*COHadd*Kb^2 + 6*COH0*Cblg*Kb^2*N1 + 6*COH0*Cblg*Kb^2*N2 + 6*COH0*Cblg*Kb^2*N3 + 6*COH0*Cblg*Kb^2*N4 + 6*COH0*Cblg*Kb^2*N5 + 6*COH0*Cblg*Kb^2*N6 + 6*COH0*Cblg*Kb^2*N7 + 2*COH0*Kb + COHadd^2*Kb^2 - 2*COHadd*Cblg*Kb^2*N1 - 2*COHadd*Cblg*Kb^2*N2 - 2*COHadd*Cblg*Kb^2*N3 - 2*COHadd*Cblg*Kb^2*N4 - 2*COHadd*Cblg*Kb^2*N5 - 2*COHadd*Cblg*Kb^2*N6 - 2*COHadd*Cblg*Kb^2*N7 + 2*COHadd*Kb + Cblg^2*Kb^2*N1^2 + 2*Cblg^2*Kb^2*N1*N2 + 2*Cblg^2*Kb^2*N1*N3 + 2*Cblg^2*Kb^2*N1*N4 + 2*Cblg^2*Kb^2*N1*N5 + 2*Cblg^2*Kb^2*N1*N6 + 2*Cblg^2*Kb^2*N1*N7 + Cblg^2*Kb^2*N2^2 + 2*Cblg^2*Kb^2*N2*N3 + 2*Cblg^2*Kb^2*N2*N4 + 2*Cblg^2*Kb^2*N2*N5 + 2*Cblg^2*Kb^2*N2*N6 + 2*Cblg^2*Kb^2*N2*N7 + Cblg^2*Kb^2*N3^2 + 2*Cblg^2*Kb^2*N3*N4 + 2*Cblg^2*Kb^2*N3*N5 + 2*Cblg^2*Kb^2*N3*N6 + 2*Cblg^2*Kb^2*N3*N7 + Cblg^2*Kb^2*N4^2 + 2*Cblg^2*Kb^2*N4*N5 + 2*Cblg^2*Kb^2*N4*N6 + 2*Cblg^2*Kb^2*N4*N7 + Cblg^2*Kb^2*N5^2 + 2*Cblg^2*Kb^2*N5*N6 + 2*Cblg^2*Kb^2*N5*N7 + Cblg^2*Kb^2*N6^2 + 2*Cblg^2*Kb^2*N6*N7 + Cblg^2*Kb^2*N7^2 + 2*Cblg*Kb*N1 + 2*Cblg*Kb*N2 + 2*Cblg*Kb*N3 + 2*Cblg*Kb*N4 + 2*Cblg*Kb*N5 + 2*Cblg*Kb*N6 + 2*Cblg*Kb*N7 + 1)^(1/2) + COH0*Kb - COHadd*Kb + Cblg*Kb*N1 + Cblg*Kb*N2 + Cblg*Kb*N3 + Cblg*Kb*N4 + Cblg*Kb*N5 + Cblg*Kb*N6 + Cblg*Kb*N7 - COH0*COHadd*Kb^2 + 1)/(2*(COH0*Kb^2 + Kb))
-(COH0*Kb - (COH0^2*COHadd^2*Kb^4 + 2*COH0^2*COHadd*Kb^3 + 4*COH0^2*Cblg*Kb^3*N1 + 4*COH0^2*Cblg*Kb^3*N2 + 4*COH0^2*Cblg*Kb^3*N3 + 4*COH0^2*Cblg*Kb^3*N4 + 4*COH0^2*Cblg*Kb^3*N5 + 4*COH0^2*Cblg*Kb^3*N6 + 4*COH0^2*Cblg*Kb^3*N7 + COH0^2*Kb^2 + 2*COH0*COHadd^2*Kb^3 - 2*COH0*COHadd*Cblg*Kb^3*N1 - 2*COH0*COHadd*Cblg*Kb^3*N2 - 2*COH0*COHadd*Cblg*Kb^3*N3 - 2*COH0*COHadd*Cblg*Kb^3*N4 - 2*COH0*COHadd*Cblg*Kb^3*N5 - 2*COH0*COHadd*Cblg*Kb^3*N6 - 2*COH0*COHadd*Cblg*Kb^3*N7 + 4*COH0*COHadd*Kb^2 + 6*COH0*Cblg*Kb^2*N1 + 6*COH0*Cblg*Kb^2*N2 + 6*COH0*Cblg*Kb^2*N3 + 6*COH0*Cblg*Kb^2*N4 + 6*COH0*Cblg*Kb^2*N5 + 6*COH0*Cblg*Kb^2*N6 + 6*COH0*Cblg*Kb^2*N7 + 2*COH0*Kb + COHadd^2*Kb^2 - 2*COHadd*Cblg*Kb^2*N1 - 2*COHadd*Cblg*Kb^2*N2 - 2*COHadd*Cblg*Kb^2*N3 - 2*COHadd*Cblg*Kb^2*N4 - 2*COHadd*Cblg*Kb^2*N5 - 2*COHadd*Cblg*Kb^2*N6 - 2*COHadd*Cblg*Kb^2*N7 + 2*COHadd*Kb + Cblg^2*Kb^2*N1^2 + 2*Cblg^2*Kb^2*N1*N2 + 2*Cblg^2*Kb^2*N1*N3 + 2*Cblg^2*Kb^2*N1*N4 + 2*Cblg^2*Kb^2*N1*N5 + 2*Cblg^2*Kb^2*N1*N6 + 2*Cblg^2*Kb^2*N1*N7 + Cblg^2*Kb^2*N2^2 + 2*Cblg^2*Kb^2*N2*N3 + 2*Cblg^2*Kb^2*N2*N4 + 2*Cblg^2*Kb^2*N2*N5 + 2*Cblg^2*Kb^2*N2*N6 + 2*Cblg^2*Kb^2*N2*N7 + Cblg^2*Kb^2*N3^2 + 2*Cblg^2*Kb^2*N3*N4 + 2*Cblg^2*Kb^2*N3*N5 + 2*Cblg^2*Kb^2*N3*N6 + 2*Cblg^2*Kb^2*N3*N7 + Cblg^2*Kb^2*N4^2 + 2*Cblg^2*Kb^2*N4*N5 + 2*Cblg^2*Kb^2*N4*N6 + 2*Cblg^2*Kb^2*N4*N7 + Cblg^2*Kb^2*N5^2 + 2*Cblg^2*Kb^2*N5*N6 + 2*Cblg^2*Kb^2*N5*N7 + Cblg^2*Kb^2*N6^2 + 2*Cblg^2*Kb^2*N6*N7 + Cblg^2*Kb^2*N7^2 + 2*Cblg*Kb*N1 + 2*Cblg*Kb*N2 + 2*Cblg*Kb*N3 + 2*Cblg*Kb*N4 + 2*Cblg*Kb*N5 + 2*Cblg*Kb*N6 + 2*Cblg*Kb*N7 + 1)^(1/2) - COHadd*Kb + Cblg*Kb*N1 + Cblg*Kb*N2 + Cblg*Kb*N3 + Cblg*Kb*N4 + Cblg*Kb*N5 + Cblg*Kb*N6 + Cblg*Kb*N7 - COH0*COHadd*Kb^2 + 1)/(2*(COH0*Kb^2 + Kb))

接着用subs函数代入数据就好了
望采纳，谢谢！

追问

为什么这条指令在我的matlab里就出现了这行error呢
Error in ==> solve at 2
solve('(COHadd - COH)/Cblg = N1*(1/(1 + Kb*COH0) - 1/(1 + Kb*COH)) +
N2*(1/(1+Kb*COH0) - 1/(1 + Kb*COH))+ N3*(1/(1 + Kb*COH0)-1/(1 + Kb*COH)) +

追答

还有问题么？