I have tried


and alternatively


Apparently both seem to work, but I was wondering what was the right way to do it? This might sound like a silly question (apologies if it is). But I am doing some tedious calculations and I don't want a silly mistake to carry forward.

Thanks in advance.

  • 1
    $\begingroup$ With a[i] = 2 compare what (a[i])^2 evaluates versus what (a^2)[i] evaluates. $\endgroup$
    – Edmund
    Oct 8, 2017 at 18:38
  • 1
    $\begingroup$ Short answer is the first. For explanation see this excellent answer. Also I suggest you read this post. $\endgroup$
    – ercegovac
    Oct 8, 2017 at 18:57

1 Answer 1


The universal answer for such kind of questions is to compare FullForms of the expessions. You will see their actual internal structure in a readable and (usually) easy-to-interpret form.

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