Devices that use a unique personal characteristic, such as a fingerprint, in place of a password are called

Awell-diversified portfolio needs about 20-25 stocks from different categories.

If your accelerator suddenly gets stuck what should you do

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.