Dicsussion Board 1

Discussion board post:

• Pick one of the exercises in the readings this week.
  
• Solve the exercise as best as you can. If you have issues, explicate them, so that all of us can help.

Exercise C25 pg. 150

Matrix - Vector Product

mat_a <- a <- matrix(c(1,2,3,-2,0,1,-2,-1,1,1,3,1), nrow = 3, byrow = TRUE)
mat_a

##      [,1] [,2] [,3] [,4]
## [1,]    1    2    3   -2
## [2,]    0    1   -2   -1
## [3,]    1    1    3    1

vec_b <- matrix(c(-7,3,1,1))
vec_b

##      [,1]
## [1,]   -7
## [2,]    3
## [3,]    1
## [4,]    1

Solution:

mat_a %*% vec_b

##      [,1]
## [1,]    0
## [2,]    0
## [3,]    0