R Notebook

The symbols or the commands to actually do it? What exactly do you want?

You can typeset the math using single or double dollar signs

\(\Sigma^{-1}\) for the symbol. Or, for the matrix. \[\Sigma^{-1} = \begin{bmatrix} 1 & .2\\ .2 & 1 \end{bmatrix}\]

To just invert it in a r code chunk, use the solve function.

#First the matrix
sample <- matrix(c(1, .2, .2, 1), nrow=2)
sample

     [,1] [,2]
[1,]  1.0  0.2
[2,]  0.2  1.0

#Then the inverse
inverse <- solve(sample)
inverse

           [,1]       [,2]
[1,]  1.0416667 -0.2083333
[2,] -0.2083333  1.0416667