clc
clear

disp('ck')
a=[3,7,15]
c=2
f=c*a
b=[1 5 -9]
g1=dot(a,b)
g2=dot(b,a)

d1=cross(a,b)
d2=cross(b,a)

11=norm(d1)
12=norm(d2)

A=[1 2 3;4 5 6;7 8 9]
D=A'
B=[1 2 3]
C1=[1; 2; 3]
C2=B'
E=[1 2; 3 4]
G=[-1 5; 9 -7]
H1=E+G
H2=E-G