Question

`{(lnx)}^(2)`

☝This equal to which one of them
Which one of them is the right wrting of that☝?​

Answer 1

I think the best way to remove all ambiguity is to write

`\bigg(\ln(x)\bigg)^2`

`\ln^2(x)` is often used to mean the same thing, but in some contexts it is used to mean the composition of logarithms,
`\ln^2(x) := \ln(\ln(x))`.

`\ln x^2` and
`\ln(x^2)` and
`\ln(x)^2` could all mean the same thing - the logarithm of the quantity
`x^2`. For real, non-zero
`x`, this is equivalent to
`\ln(x^2) = 2\ln|x|`, but this is not true for either of the squared- or compound-logarithm interpretations.

`\bigg(\ln(x)\bigg)^2` very clearly shows what's being squared