a. Calculates the sum of all things in m that are greater than 5.
- m > 5 returns a 1 for all entries that are greater than 5 and a 0
for the others
- m(m > 5) returns a new matrix only containing those values that were
greater than 5
b. Calculates the sum of all things in m that are greater than 5.
m .* (m > 5) will be a matrix the same size as m, but with all of the
entries that were not > 5 will be zero. Taking the sum twice of this
matrix then gives us overall sum of these values.
c. The number of entries in m where the value squared is greater than 5.
'.*' has a higher precedence than '>' so we first multiply each value
in m by itself (i.e. square it), then see if that value is > 5.