INVERS

Sifat-Sifat Operasi Matriks dan Invers Matriks

library(matlib)
X <-  matrix(c(5,-3,-1,2,7,2,7,-3,1), nrow = 3, ncol = 3)
plotEqn(X)

##  5*x[1] + 2*x[2]  =   7 
## -3*x[1] + 7*x[2]  =  -3 
##   -x[1] + 2*x[2]  =   1

Kemudian kita balik matrix tersebut

B <-inv(X)
B

##            [,1]       [,2]        [,3]
## [1,] 0.15476190  0.1428571 -0.65476190
## [2,] 0.07142857  0.1428571 -0.07142857
## [3,] 0.01190476 -0.1428571  0.48809524

plotEqn(B)

##  0.1547619*x[1] + 0.14285714*x[2]  =   -0.6547619 
## 0.07142857*x[1] + 0.14285714*x[2]  =  -0.07142857 
## 0.01190476*x[1] - 0.14285714*x[2]  =   0.48809524

library(MASS)
fractions(B)

##      [,1]   [,2]   [,3]  
## [1,]  13/84    1/7 -55/84
## [2,]   1/14    1/7  -1/14
## [3,]   1/84   -1/7  41/84