Purple Math
Purplemath: Mean, Median, Mode, and Range
Mean, median, and mode are three kinds of "averages". The "mean" is the "average" you're used to, where you add up all the numbers and then divide by the number of numbers. The "median" is the "middle" value in the list of numbers. To...
Purple Math
Purplemath: Matrix Inversion: Finding the Inverse of a Matrix
Inverse matrices are very useful for solving matrix equations. But, given a matrix, how do you invert it? How do you find the inverse? The technique for inverting matrices is kind of clever. For a given matrix A and its inverse A-1, we...