How can I adapt a summation function (see below) with a for loop to create a "x to the power of n" function without using the "^" operator?

Hey All!

Below is a simple "sum" function.

function [answer] = sum (n)
    answer = 0;
    for i = 1:n
        answer = answer + i;
    end
end

My question is - how can i turn/adapt this sum function into x^n function, without using the "^" operator and only using the definiton of the exponent i.e. x^n = x x x x x x x (n times)

Thanks and i hope i formulatedt this question properly!

Rohit

[per isakson]

Homework? If so, what have you done so far?

[Rohit Kumar Sil]

It's more like a practice question from uni.

Well i tried to start out by following a similar path to when i figured out the intial sum function, which basically displayed Σ(i) from i =1 to 100.

And now i was trying to figure out how i could adapt the aforementioned formula to design a for loop for a basic x^n exponential function.

I have this so far ( no idea if its ok because it's the first time I'm using 2 independant variables in the for loop i.e. n and x) which is really not alot...

function [answer] = exponent(x,n)
x=0; %initialization
n=0; %initialization
for i = 0:n
...

;(

[per isakson]

Seriously, it's not a good idea to overwrite the input arguments!

Answer 1

[madhan ravi]

I mean is the loop necessary?

n=4;
cumsum(repmat(2,1,n))   % 2 is x here

if you still insist:

answer = sum1(x,n) %function call

function answer = sum1(x,n)  %changed sum to sum1 because it will contradict with the inbuilt function
answer=zeros(1,n); % pre-allocation
answer(1) = x;
for i = 2:n   
    answer(i)=answer(i-1)*answer(1);
end 
answer;
end

[Rohit Kumar Sil]

Hi again!

according to the problem instructions that i'm currently doing yes - it specifically says that i need to adapt the "sum" function i displayed below...

Rohit

[Rohit Kumar Sil]

First of all thank you!

I had one question -

1) what exactly does "answer(1) = x;" signify?

[madhan ravi]

Anytime :) , make sure to accept the answer if it helped you , it defines the first element of the array learn about array indexing in matlab

Answer 2

[per isakson]

Try

function [answer] = raised(x,n)
    answer = 1;
    for ii = 1:n
        answer = answer * x;
    end
end

and test

>> raised( 3, 4 )
ans =
    81