Black_Scholes(t, S, r, sigma, K, T, type=c("call", "put"))
Black_Scholes_Greeks(t, S, r, sigma, K, T)character string indicating whether the price
of a call (the default) or of put option is to be computed.Black_Scholes() returns the value of a European-style call or put
option (depending on the chosen type) on a non-dividend paying stock. Black_Scholes_Greeks() returns the first-order derivatives
delta, theta, rho, vega and the second-order derivatives gamma, vanna
and vomma (in this order).