Write a MATLAB script to return the vector of powers of a number

Hello, I need to write MATLAB script with the function `powers(x, n)`, which will return a vector with first `n˙ powers of number `x`.

[Torsten]

Write a MATLAB script to return the vector of powers of a number

A script doesn't return anything - functions do. Maybe before starting you should learn the basics of MATLAB in an online course free of costs:

https://matlabacademy.mathworks.com/details/matlab-onramp/gettingstarted

If you don't want to do that or don't have the time, we need at least an attempt from your side to solve the exercise in order to help.

[andrej]

function result = powers(x, n)
%POWERS returns the vector of first n powers of x
%   result = powers(x, n) returns a vector, which contains x^1, x^2, ..., x^n

result = zeros(1, n); % Initialization of result

for i = 1:n
    result(i) = x^i;
end
end

[Walter Roberson]

It is not immediately clear that the results are all correct.

powers(2, 5)

ans = 1×5

2 4 8 16 32

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powers(-1, 6)

ans = 1×6

-1 1 -1 1 -1 1

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powers(3, -2.5)

ans =

  1×0 empty double row vector

powers(0, 0)

ans =

  1×0 empty double row vector

try
    powers(3, 4:6)
catch ME
    warning(ME.message)
end

Warning: Size inputs must be scalar.

try
    powers(-1:1, 3)
catch ME
    warning(ME.message)
end

Warning: Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To operate on each element of the matrix individually, use POWER (.^) for elementwise power.

function result = powers(x, n)
%POWERS Vrne vektor prvih n potenc števila x
%   result = powers(x, n) vrne vektor dolžine n, ki vsebuje x^1, x^2, ..., x^n

result = zeros(1, n); % Inicializacija rezultata

for i = 1:n
    result(i) = x^i;
end
end

[DGM]

I think the suggestion here is that you need to decide how x and n are to be specified -- i.e. whether they're scalars or arrays.

Given the code, I'm going to assume both x and n are strictly scalar, and you only want strictly positive integer powers.

% inputs
x = 2;
n = 8;

% result in one line
y = x.^(1:n)

y = 1×8

2 4 8 16 32 64 128 256

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Of course, you'd have to roll that into a script, but

Answer 1

[Sulaymon Eshkabilov]

Maybe to have a few different options embedded in the function file, e.g.:

clearvars
%% Case # 1.
x = [2.2 3:5]; n = [1.5 3 2];
% %% Case # 2.
% x = 5; n = 3;
% %% Case # 3.
% x = 2; n = [2 4 5];
% %% Case # 4.
% x = 2:5; n = 3;

%%  Test the cases:

if numel(x)>1 & numel(n)>1        % Case #1.
Result = POWERs(x,n)
elseif numel(x)==1 & numel(n)==1  % Case #2.
    Result=x.^(1:n)
elseif numel(x)==1 & numel(n)>1   % Case #3.
Result = x.^(n)   
else  % numel(x)>1 & nume(n)==1   % Case #4.
    Result = POWERs(x,n)
end

Result = 4×3

3.2631 10.6480 4.8400 5.1962 27.0000 9.0000 8.0000 64.0000 16.0000 11.1803 125.0000 25.0000

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function Result = POWERs(x, n)
if numel(x)>1 & numel(n)>1
for ii=1:length(x)
    for jj = 1:length(n)
        Result(ii, jj)=x(ii)^(n(jj));
    end
end
else
  for ii=1:length(x)
      Result(ii, :)=x(ii).^(1:n);
    end
end
end