Write a Matlab code that computes the following sum while requesting the value of x and n from the user.

The Correct Answer and Explanation is:

✅ Correct MATLAB Code:

matlabCopyEdit% Request user input for x and n
x = input('Enter a positive integer value for x: ');
n = input('Enter a positive integer value for n: ');

% Check if x and n are positive integers
if ~isscalar(x) || ~isscalar(n) || x <= 0 || n <= 0 || floor(x) ~= x || floor(n) ~= n
    disp('Error: Both x and n must be positive integers.');
else
    y = 0;
    for k = 1:n
        y = y + (2 / x)^k;
    end
    fprintf('The computed value of y is: %.4f\n', y);
end

🔍 Explanation

This MATLAB code calculates a mathematical sum defined as:y=∑k=1n(2x)ky = \sum_{k=1}^{n} \left(\frac{2}{x}\right)^ky=k=1∑n​(x2​)k

The goal is to prompt the user to input two values: x and n, which must be positive integers. These inputs are taken using the input function.

Before proceeding with the computation, the code performs a validation step. It checks whether x and n are:

  1. Scalars (not vectors or matrices),
  2. Greater than zero,
  3. Whole numbers (integers).

This validation is done using the logical conditions:

  • isscalar(x) and isscalar(n) ensures the inputs are single values,
  • x > 0 and n > 0 ensure positivity,
  • floor(x) == x and floor(n) == n ensure integer values.

If any of these checks fail, the program displays an error message and halts.

If the inputs are valid, a for loop is used to calculate the sum. The loop runs from k = 1 to n, and in each iteration, it adds the term (2x)k\left(\frac{2}{x}\right)^k(x2​)k to the running total y.

Finally, the result is displayed using fprintf, which allows formatted output. The format %.4f is used to show the result with four decimal places for clarity.

This implementation ensures user input is verified before mathematical operations begin, preventing invalid calculations and improving robustness.

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