How to get the coefficients of an equation

Question

Geovane Gomes 2023-11-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2044742-how-to-get-the-coefficients-of-an-equation

回答： Sulaymon Eshkabilov 2023-11-8

采纳的回答： Dyuman Joshi

在 MATLAB Online 中打开

Dear all,

Is it possible to extract the coefficients of an equantion defined as below:

syms x1 x2

eq = 2*x1 + x2 <= 0

eq =

By using coeffs and sym2poly did not work when it has the relational operator "<=".

c = coeffs(eq)
c = 1
c = sym2poly(eq)
Error using sym/sym2poly
Not a polynomial.

2 个评论
显示无隐藏无

Dyuman Joshi 2023-11-8

What is the expected output?

[1 2] or [2 1]? or something else?

Geovane Gomes 2023-11-8

[2 1]

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Dyuman Joshi 2023-11-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2044742-how-to-get-the-coefficients-of-an-equation#answer_1348972

在 MATLAB Online 中打开

How about -

syms x1 x2

eq = 2*x1 + x2 <= 0

eq =

out = flip(coeffs(lhs(eq)))

out =

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Geovane Gomes 2023-11-8

在 MATLAB Online 中打开

Good solution!

This way I can also have the term in the right side

syms x1 x2

eq = 2*x1 + x2 <= 5

eq =

out = flip(coeffs(rhs(eq)))

out =

5

Thanks!

请先登录，再进行评论。

Answer 2

Sulaymon Eshkabilov 2023-11-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2044742-how-to-get-the-coefficients-of-an-equation#answer_1348987

在 MATLAB Online 中打开

Maybe it is appropriate to work in a reverse order, e.g.:

syms x1 x2

Coeff = [2;1];

eq = [x1, x2]*Coeff<=0

eq =

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。