Backward Finite-Div​ided-Diffe​rence Coding

g = input('Enter the function: e.g @(x) sin(x): ','s');

f = str2func(g);

h = input('Enter step size, H: ');

x = input('At which point you want to approximate the derivative: ');

Bd2 = (f(x)-f(x-h))/h;

fprintf('Backward FDD: %.4f',Bd2)

How do I make my coding to compute this function @(x) -0.3757*x+5

[Ashutosh]

It works as expected for me, what is the error message you are getting?

[Kim]

Error using str2func Argument must be a text scalar. Error in BDD (line 9) f = str2func(g);

Answer 1

[Nivedita]

Hello Adrian,

I understand that you want to compute the function @(x) -0.3757*x+5 with the provided code.

I executed the provided code and it worked as expected from the definition of the "Bd2" variable providing a result of 0.3757.

If you are facing any difficulty with the "str2func" function and obtaining the same error as mentioned by Kim, you can take care of the following pointers:

1. Ensure that there are no extra characters or spaces in the function expression stored in "g".
2. Verify that the function expression in "g" follows the correct syntax as you have mentioned in your question.

For more information on the "str2func" function, please refer to the following documentation link:

https://www.mathworks.com/help/matlab/ref/str2func.html

I hope it helped!

Regards,

Nivedita.