Substitute an array of number for a symbolic variable
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David Arnold
on 1 Nov 2012
Commented: Walter Roberson
on 12 Jul 2019
Hi,
I have:
syms x y
f=x^3+y^3+3x^2+2y^2+9
fx=diff(f,x)
now, I'd like to substitute these two vectors of x and y values into the expression fx.
x=[1,2,3,4,5]
y=[6,7,8,9,10]
How do I do that with the subs command? If I can't do that with the subs command, what do you recommend?
David.
1 Comment
Star Strider
on 1 Nov 2012
Edited: Star Strider
on 1 Nov 2012
Question: Do you want a matrix with the function evaluation of fx for each value of (x,y) as an individual element?
What version of MATLAB do you have? Beginning with 2012a, symbolic functions are possible.
Accepted Answer
Walter Roberson
on 1 Nov 2012
subs(fx, {x, y}, {[1,2,4,5,6}, [6,7,8,9,10]})
This syntax is documented relatively far down in the examples.
More Answers (1)
Azzi Abdelmalek
on 1 Nov 2012
syms x y
f=x^3+y^3+3*x^2+2*y^2+9
fx=diff(f,x)
x=[1,2,3,4,5]
y=[6,7,8,9,10]
eval(f)
eval(fx)
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