Cannot find explicit solution
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I am trying to solve a nonlinear equation with one unknown:
syms eps a k f b e c d g w h ct m n
solve((-(w*(c*(f*k)^(1/(k + 1)) + d*(e*k)^(1/(k + 1))))/(4*eps*w - ct*w + n*w + g*(f*k)^(1/(k + 1))))^(k + 1) + (-(w*(a*(f*k)^(1/(k + 1)) + h*(e*k)^(1/(k + 1))))/(4*eps*w - ct*w + m*w + g*(f*k)^(1/(k + 1))))^(k + 1) == ((b*w*(e*k)^(1/(k + 1)))/(2*eps*w - ct*w + m*w + n*w + g*(f*k)^(1/(k + 1))))^(k + 1) + w^(k + 1), w>=0, eps>0, a>0, b>0, c>0, d>0, e>0, f>0, g>0, h>0, k>0, ct>0, m>0, n>0, w)
But Matlab says:
Warning: Cannot find explicit solution.
> In solve (line 316)
ans =
Empty sym: 0-by-1
Any idea?
Thanks.
回答（2 个）
Roger Stafford
2016-5-29
I’m afraid you will just have to take solve’s word for it that it cannot find an explicit solution to your equation. I believe it is the presence of the term “w^(k+1)” that prevents a solution being found.
The way around this is to abandon symbolic solutions and obtain a numerical solution. This will require that you assign specific numerical values to all the parameters: k, c, d, e, etc. You can use matlab’s ‘fzero’ for this purpose. Read about it at:
http://www.mathworks.com/help/matlab/ref/fzero.html
Walter Roberson
2016-5-29
0 个投票
I do not know why it cannot find the solution, but the solution is w = 0, provided k is not -1
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2016-5-29
2016-5-29
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