In R pls

1.2 Use the following script, we can generate a 3X4 matrix tmpc-matrix(rnorm(12), 3, 4) Answer the following questions. (1) Compute the sum of the first and third column. (2) Compute the product of the first and third row. (3) Show the dimension of the matrix. (4) Use cat' function to output elements in the first row that are larger than 0.5