evalAt() does not work any way I use it
显示 更早的评论
When I try using evalAt() function I always get an error. I have tried using it in many different ways.
Example 1:
y=x^2;
evalAt(y, x=3)
Error: File: plot_test.m Line: 2 Column: 12
The expression to the left of the equals sign is not a valid target for an assignment.
I also tried to use subs() and still get error.
I also tried reinstalling MATLAB and did not work.
I will really appretiate any help, Thanks
3 个评论
Walter Roberson
2012-10-19
Which MATLAB version are you using? That syntax has only been valid since R2012a.
Walter Roberson
2012-10-19
Yes, but the ability to use "=" in a symbolic expression (as opposed to assignment) is new in R2012a.
subs(y, x, 3)
not
subs(y, x=3)
采纳的回答
Star Strider
2012-10-19
编辑：Star Strider
2012-10-19
Starting with 2012a, you can Create Symbolic Functions. This is probably the easiest way to do what you want:
syms x y
y(x) = x^2
z = y(3)
giving this result:
y(x) =
x^2
z =
9
更多回答（3 个）
What do you see when you type these? Do you see the help, or do you see function not found?
help evalAt
help subs
If you see 'function not found', then you don't have the symbolic toolbox installed, or you don't have a license checked out.
Sachin Ganjare
2012-10-19
编辑：Sachin Ganjare
2012-10-19
0 个投票
Most probably you do not have 'Symbolic Math Toolbox' installed on your system. Check using 'ver' command.
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