Use module_info on Erlang modules you wish to inspect:
iex> :math.module_info
[module: :math,
exports: [pi: 0, module_info: 0, module_info: 1, pow: 2, atan2: 2, sqrt: 1,
log10: 1, log2: 1, log: 1, exp: 1, erfc: 1, erf: 1, atanh: 1, atan: 1,
asinh: 1, asin: 1, acosh: 1, acos: 1, tanh...