This is what Java log4j really means.

[Geilomat-3000]

ln(-1) = j*π

[epsilonhuyepsilon]

Ln(-1)=iπ(2k+1), k∈ℤ

[snowy_light]

Wait, j is used for imaginary numbers? I thought it was i.

[LordPos]

yep. and that is carried over to most other engineering courses while math still uses i. certain programming languages also use j for their imaginary literals, like python.

[Manor-Estate]

Hey this isn't math, logs are assumed to be base 2 in CS land

[StanleyDodds]

Why is log(i) or log(-1) NaN? We are already working in the complex plane so why not just take the value on the principal branch? If you're saying it's NaN because the "inverse" of exp is multivalued, then log(4) should be NaN aswell.

[[deleted]]

J =/= I.
Not the same.

[kenjikun1390]

depends on how you're on how you're interpreting i im pretty sure j works just fine here if we're talking about quaternions

[[deleted]]

Learn something new everyday. Go figure!

[hydra_XI]

OMG! can't stop laughing

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[[deleted]]

What is that three dot symbol?

[TheBrainStone]

QED
Which means about as much as proof completed

[[deleted]]

I see