Using complete sentences post a detailed response to the following. Consider the various methods for authentication: passwords, biometric verification, and security tokens. For each kind of authentication, describe one real-world application where that level of security makes the most sense or is used widely, and explain why it is a sensible choice.

Least square fit to polynomial write a function leastsquarefit3pol that solves a linear system of equations to find a least squares fit of a third order polynomial to an experimental data set given as two row arrays. the function leastsquarefit3pol must explicitly solve a set of linear equations and cannot use polyfit. there should be no restriction on the size of the problem that can be solved.