How to differentiate a series of functions denoted by varying a parameter i=1,2 in (h_i)?

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Asit Srivastava
Asit Srivastava 2020-2-23
评论： Asit Srivastava 2020-2-24
I typed the following code and command window displays unrecognised function h_i. If I remove the outer loop and replace "i" with some number, say "2", then it displays unrecognised function x_j. What's the mistake?
clc
clear all
syms x_1 x_2
h_1(x_1,x_2)=x_1+(x_2)*(x_1);
h_2(x_1,x_2)=x_2+x_1*x_2^2;
for i=1:2
for j=1:2
diff(h_i,x_j)
end
end

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采纳的回答

darova
darova 2020-2-23
编辑：darova 2020-2-23
Mistake that h_1 and h_i and different variables
m1stake = 2;
m2stake = 3;
for i = 1:2
disp(mistake) % doesn't work
end
Use arrays and cells
clc
clear all
syms x_1 x_2
h_1(x_1,x_2)=x_1+(x_2)*(x_1);
h_2(x_1,x_2)=x_2+x_1*x_2^2;
X = {x_1 x_2};
H = {h_1 h_2};
for i=1:2
for j=1:2
diff(H{i},X{j})
end
end

更多回答（1 个）

Image Analyst
Image Analyst 2020-2-23
Don't use a loop. For just 4 cases, just write them out
h_1(x_1,x_2) = x_1 + (x_2) * (x_1);
h_2(x_1,x_2) = x_2 + x_1 * x_2^2;
diff(h_1,x_1)
diff(h_1,x_2)
diff(h_2,x_1)
diff(h_2,x_2)
  3 个评论
显示 1更早的评论
Image Analyst
Image Analyst 2020-2-23
You don't have 56 separate and differently named variables, do you? If so, you really need to learn how to use arrays.

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