MATH
21 B
Mathematics Math21b Spring 2017
Linear Algebra and Differential Equations
Linear algebra Math21b, Spring 2017
Course Head: Oliver Knill
Office: SciCtr 432
  • In HW 12, the formula for the regression line had a factor missing. The slope is Cov[x,y]/Var[x] = X.Y/|X|^2. Here is some mathematica code for an other data set:
    d=Table[{k,Prime[k]},{k,30}];
    f = Fit[d,{1,t},t];   n = Length[d];
    x = Map[First, d];   y = Map[Last, d];
    X = x - Total[x]/n;  Y = y - Total[y]/n;
    a = X.Y/(X.X); b = Total[y]/n - a Total[x]/n;
    a t + b== f
    Show[{Plot[f,{t,Min[x],Max[x]}],
          Graphics[Table[Point[d[[k]]],{k,n}]]}]
    
  • We have a global course wide review on Sunday, 2/26/2017 at 7 PM in Hall C.
  • Our first midterm takes place at 7 PM on Tuesday February 28, 2017 in Lecture Hall B.
  • Practice exams for the first hourly are posted on the Exams page
Please send questions and comments to knill@math.harvard.edu
Math21b Harvard College Course ID:110989| Oliver Knill | Spring 2017 | Department of Mathematics | Faculty of Art and Sciences | Harvard University, [Canvas, for admin], Twitter