Hello David, the command you can use is ROOT, you need an 'expression' or 'equation' with one unknown, the name of the 'unknown' and a guess value, it could be like this:
<<
'100000 = LOG(2*PI*N)/2 + N*LOG(N/e)'
'N' 10 ROOT
<<
'100000 = LOG(2*PI*N)/2 + N*LOG(N/e)'
'N' 10 ROOT
>>I hope this helps.