Check for missing argument or incorrect argument data type in call to function 'expand'

After using sym2poly to get the coefficients of a polynomial, I get the following : B = 1.0e+07 * 0.0000 0.0003 0.0103 2.5110 2.6503 -0.0500 Then I am trying to multiply the 1.0e+07 by the vector, so I used expand(B). It gives the following error Check for missing argument or incorrect argument data type in call to function 'expand'. How can I expand that expression anyway?

Answer 1

[Ayush]

Hi @Priyanshu,

The “expand” function in MATLAB is used to expand and simplify symbolic expressions. However, in your case, you have a numeric vector “B” obtained from “sym2poly”, which means it contains numeric coefficients rather than symbolic expressions.

To perform the multiplication of the entire vector “B” by 1.0e+07, you don't need to use “expand” function. You can simply multiply the vector by the scalar value directly. Here’s a snippet representing the operation:

format long 
B = [0.0000, 0.0003, 0.0103, 2.5110, 2.6503, -0.0500]; 
multiplied_B = 1.0e+07 * B

multiplied_B = 1×6

1.0e+07 * 0 0.000300000000000 0.010300000000000 2.511000000000000 2.650300000000000 -0.050000000000000

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So, “B” is your numeric vector and “multiplied_B” will store the result of multiplying each element of “B” by 1.0e+07.

Note that there is no need to use expand in this case since you are dealing with numeric values rather than symbolic expressions. Also, "format long" is used to provide both high precision and flexibility in scientific or fixed-point notation.

Hope it helps!

Answer 2

[Walter Roberson]

I get the following : B = 1.0e+07 * 0.0000 0.0003 0.0103 2.5110 2.6503 -0.0500

Give the command

format long g

and display the results again.