Discussion2_Prob3_Page351

3. Compute the determinant of the given matrix.

# 3. Compute the determinant of the matrix
# 3 9 -2 4 2
# 0 1 4 -2 7
# 0 0 -2 5 2
# 0 0 0 -1 6
# 0 0 0 0 4


m <- matrix(data = c(3, 9, -2, 4, 2,
                     0, 1, 4, -2, 7,
                     0, 0, -2, 5, 2,
                     0, 0, 0, -1, 6,
                     0, 0, 0, 0, 4), nrow = 5, ncol = 5, byrow = T)

print(m)

##      [,1] [,2] [,3] [,4] [,5]
## [1,]    3    9   -2    4    2
## [2,]    0    1    4   -2    7
## [3,]    0    0   -2    5    2
## [4,]    0    0    0   -1    6
## [5,]    0    0    0    0    4

# Compute determinant by hand:

d <- 3*(1*(-2*(-4)))

print(d)

## [1] 24

# Also check with R's computed result:
print(det(m))

## [1] 24