Given the array A $=[2,4,1$; $6,7,2$; $3,5,9],$ provide the commands needed to

a$)$ Assign the first row of A to a vector called x$1$

b$)$ Assign the last $2$ rows of A to an array called Y

c$)$ Compute the sum over the columns of A

d$)$ Compute the sum over the rows of A

e$)$ Compute the standard deviation of each column of A

f$)$ Compute the mean of each column of A