Can confirm it works fine with wine / proton

It is just a definition, but it's the only definition of the complex exponential function which is well behaved and is equal to the real variable function on the real line.

Also, every identity about analytical functions on the real line also holds for the respective complex function (excluding things that require ordering). They should have probably explained it.

Linnutee in Estonian, literally "bird's path" because of the birds migrating south for the winter using it for navigation.