Hi,

This question is driving me crazy.

I'm trying to get the answer provided by filling in the missing steps. See screenshot of problem below

I've got the solution using euler's formula but want to work with the exponentials.

I realise it's probably just simply work with indices but I keep going work somewhere.

Sorry for posting a screenshot instead of latex formula but I've forgotten how to use latex as I haven't visited this forum in a while.

Thanks