This array index is invalid for this array

[hrishibhor]

I need some help with a code I am writing.

I am getting an error

"This array index is invalid for this array"

attached is the code

[StuartBruff]

I think it might be because you have assigned the new value to Δudotdot_i instead of udotdot_i at the end of the for loop.

Stuart

[hrishibhor]

You were right Stuart.

The reason I got confused was that I had a similar mathcad sheet (actually a complex version of what I sent earlier) which did not have the "udotdot_i "error you caught but still showed similar error "This array index is invalid for this array"

Attached is that sheet. Could you please look through it. I think I am doing something wrong with the for loop but I might be wrong.

Appreciate your help.

[Fred_Kohlhepp]

For what ever reason, changing the range variable in your uuu() function from i to something else let the program work. (I don't understand why.)

[Werner_E · Accepted solution]

Attached is that sheet. Could you please look through it. I think I am doing something wrong with the for loop but I might be wrong.

It's only a simple typo. At the begin of your i-loop you have written Y[i+i which should be Y[i+1.