matlab does not simplify the expression?
显示 更早的评论
Hi Everyone,
I would like to find the code to convert the expression (x^10)^1/5 into x^2 but I can't find it. I'm actually trying to come up with an algorithm to solve the SVD. But when trying to find the eigenvectors i have to solve a system of equations with infinite solutions and that's where I get stuck. X1 is defined as follows
X1 =
x1
x2
and I would like to execute
ecua1=X(1); L=sqrt(X1(1)^2 + (solve(ecua1,'x2'))^2)
but in the last line
L=sqrt(X1(1)^2 + (solve(ecua1,'x2'))^2) ---> L = 2^(1/2)*(x1^2)^(1/2)
matlab does not simplify the expression and thus I can't continue.
Please, I would really appreciate any help!!
Thanks,
Paola
回答（3 个）
syms x
simplify((x^10)^(1/5),'IgnoreAnalyticConstraints',true)
2 个评论
PAOLA
2012-10-1
Walter Roberson
2012-10-1
R2009b had only very simple constraint management when you call simplify() from the MATLAB level instead of from within MuPAD itself. See the sym() command for how to constrain x to be real-valued.
Walter Roberson
2012-9-29
0 个投票
(x^10)^(1/5) is not generally x^2. p^(1/5) has five complex roots, so (x^10)^(1/5) needs to have 5 solutions, but x^2 is only a single value.
In order to get the simplification you have in mind, you will need to add assumptions of real-valued and non-negative.
1 个评论
Luan Trinh
2014-11-27
Could you help me simplify this function?
syms a si f(si) = (a^2*(51056921947406336*exp(-si*2*i) + 51056921947406336*exp(si*2*i) + 12827342454285926*exp(-si*4*i) + 12827342454285926*exp(si*4*i) + 3572093376318669*exp(-si*6*i) + 3572093376318669*exp(si*6*i) + 301903902754734080)^2)/48357032784585166988247040000000000 ;
Thank you so much.
类别
在 帮助中心 和 File Exchange 中查找有关 Numeric Solvers 的更多信息
2014-11-27
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
