Sum using vectorized commands and colon operator instead of loops.

So, first of all I better say that this isn't a homework assignment. It's a sheet of problems given to us which we can attempt in our own time to help get a feel for the final exam. The problem asks you to compute the sum of 1/(k)^3 from 1 to 1000 without using loops. I can't actually afford MATLAB on my laptop and currently am not in college, so I can't test this code but this is what I came up with off the top of my head:

x = [1:1000]; %creates vector of 1 - 1000
x(1:1000) = 1/(x(1:1000))^3; %replaces each element of that array with the inverse cubed of said %element 
a = Sum(x); %Sums up all the values of the new x                 
disp(a) %displays the value of the sum.

So, does the above code actually make sense of have I gone wrong somewhere? Thanks in advance.

Answer 1

[Wayne King]

Yes, it basically makes sense although what you have would not actually work in MATLAB because you need the "dot" operator for element-by-element operations.

And you have some unnecessary code

 k = 1:1000;
 y = 1./k.^3;
 sum(y)

[David]

Brilliant. Completely forgot about the dot operator. Thanks.