p1_mrg_matrix4 -- Sage

#1) a=matrix(3,3,(1,2,3,4,5,6,7,8,-9));a

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{rrr} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & -9 \end{array}\right)$

det(a)

 $\newcommand{\Bold}[1]{\mathbf{#1}}54$

b=matrix(1,3,(26,9,19));b

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{rrr} 26 & 9 & 19 \end{array}\right)$

c=b*a;c

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{rrr} 195 & 249 & -39 \end{array}\right)$

d=c*a**(-1);d

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{rrr} 26 & 9 & 19 \end{array}\right)$

#2) a=matrix(3,3,(2,0,4,0,1,4,1,1,-1));a

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{rrr} 2 & 0 & 4 \\ 0 & 1 & 4 \\ 1 & 1 & -1 \end{array}\right)$

b=matrix(3,1,(14,28,0));b

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{r} 14 \\ 28 \\ 0 \end{array}\right)$

a**(-1)*b

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{r} -3 \\ 8 \\ 5 \end{array}\right)$

#3) a=matrix(3,3,(1,1,1,.065,.07,.09,0,2,-1));a

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{rrr} 1.00000000000000 & 1.00000000000000 & 1.00000000000000 \\ 0.0650000000000000 & 0.0700000000000000 & 0.0900000000000000 \\ 0.000000000000000 & 2.00000000000000 & -1.00000000000000 \end{array}\right)$

b=matrix(3,1,(45000,2925,0));b

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{r} 45000 \\ 2925 \\ 0 \end{array}\right)$

n(a**(-1)*b,digits=7)

 $\newcommand{\Bold}[1]{\mathbf{#1}}\left(\begin{array}{r} 45000.00 \\ -5.820766 \times 10^{-11} \\ 0.0000000 \end{array}\right)$

p1_mrg_matrix4

3443 days ago by LAC2011