Expanding a function in Matlab

Question

Teoman Selcuk 2021-11-14

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https://ww2.mathworks.cn/matlabcentral/answers/1586574-expanding-a-function-in-matlab

评论： John D'Errico 2021-11-14

I ma trying to writea code that expands the function (a + b).^2 into the expected output. Instead it gives the Output below. How would i be able to get to the Expected Output?

>> a = 'a';
>> b= 'b';
>> func = multip = (a + b).^2

Expected Output:

a^2+2ab+b^2

Output:

7414875

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Answer 1

DGM 2021-11-14

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Using symbolic tools:

syms a b

f = expand((a+b)^2)

f =

Your approach would ostensibly return a number because you're treating characters as numbers.

double('a')
ans = 97
double('b')
ans = 98
(97+98)^2
ans = 38025

As to why exactly that number is different than what you got, I have no idea. The code you posted shouldn't do anything but throw an error.

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John D'Errico 2021-11-14

在 MATLAB Online 中打开

I assume you are saying that what would throw an error is the line with func. Of course that is invalid MATLAB syntax.

a = 'a';
b = 'b';
func = multip = (a + b).^2

I note that

sqrt(7414875)
ans =
      2723.02680853494

is not even an exact integer, but it is also far too large to be the sum of two standard ascii equivalents. So I have no immediate idea what was actually stored in those variables.

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