How to solve an equation and build a vector using a for loop?

I'm trying to solve the equation below using a for loop just to make the coding a little bit neater. Heres's the problem. And here is my code:

r = 0:0.0025:0.0175; %radius values
for i = 0:8 % values
    dela_delv = -r(i).*(r(i)-r(i+1));% equation
end

I keep getting the error: Array indices must be positive integers or logical values. Error in ME_345_Lab_5 (line 128) dela_delv(i) = -r(i).*(r(i)-r(i+1));% equation >> Some help and guidance would be very much appreciated. TIA

Answer 1

[Star Strider]

Note that zero is not a positive integer. Positive integers are integers greater than zero.

Try this:

r = 0:0.0025:0.0175; %radius values
for i = 1:numel(r)-1 % values
    dela_delv(i) = -r(i).*(r(i)-r(i+1));    % equation
end

Also, ‘r(i+1)’ does not exist if you are using every value of ‘r’ in the array, so I shortened the loop by 1 to avoid this problem.