Subs command substituting the values of variables that was earlier define symbolic but when I am using plot command error message came "Non numeric data"

Question

UB 2022-1-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1632560-subs-command-substituting-the-values-of-variables-that-was-earlier-define-symbolic-but-when-i-am-usi

评论： UB 2022-1-21

采纳的回答： KSSV

I have the expression det k in symbolic bc and kh.

detk= k31*k22-k32*k21

bc is replaced by om/kh, om is symbolic too

val=subs(detk,{bc,kh},{om/kh,kh})

der=-diff(val,kh)/diff(val,om)

mega=ub*nb % ub=2, nb=1

xx=subs(der,[om,kh],[mega,nb])

wnen code is running, expression of xx comes but not in simplified form. It contains operators *, /, sinh, cosh etc. and wnen I am trying to plot it error message came that non numeric data and plot is not supported.

plot(kh,xx)

Error using plot

Non-numeric data is not supported in 'Line'

Error in cal (line 233)

plot(kh,xx)

2 个评论
显示无隐藏无

Stephen23 2022-1-21

编辑：Stephen23 2022-1-21

After SUBS call DOUBLE: https://www.mathworks.com/help/symbolic/double.html

The Symbolic Toolbox documentation has an entire section of the function list entitled "Conversion Between Symbolic and Numeric": https://www.mathworks.com/help/symbolic/referencelist.html?type=function

UB 2022-1-21