Find the least squares polynomials of degrees 1 and 2 for the data in the fol- lowing table. Calculate the error E2 in each case. Plot the graph of the data and the polynomials.

xi 0.0 0.523598 0.785398 1.047197 1.570796

yi 2.718281 2.377443 2.028115 1.648772 1.0