sss / 14_Кириллова_03а.doc

упражнение 3.9

>> grid on

xlabel('X'),ylabel('Y'),zlabel('Z')

axis square

box on

>> hold on

>> plot3(1,0,0,'>k','linewidth',4)

>> line([0;1],[0;0],[0;0],'color','k','linewidth',4)

line([0;0],[0;1],[0;0],'color','k','linewidth',4)

line([0;0],[0;0],[0;1],'color','k','linewidth',4)

>> plot3(0,1,0,'>k','linewidth',4)

>> plot3(0,0,1,'>k','linewidth',4)

>>>> line([0;1],[0;-2],[0;0],'color','r')

>> line([0;0],[0;1],[0;1],'color','r')

>> line([0;1],[0;2],[0;2],'color','r')

>> line([0;1/5^0.5],[0;-2/5^0.5],[0;0])

>> line([0;0],[0;1/2^0.5],[0;1/2^0.5])

>> line([0;1/3],[0;2/3],[0;2/3])

>>

упражнение 3.10(В)

>> A=[2,1,1;1,1,0;0,1,-1]

A =

2 1 1

1 1 0

0 1 -1

>> res=A(1,1).*A(2,2).*A(3,3)+A(2,1).*A(3,2).*A(1,3)+A(1,2).*A(2,3).*A(3,1)-A(1,3).*A(2,2).*A(3,1)-A(1,1).*A(3,2).*A(2,3)-A(2,1).*A(1,2).*A(3,3)

res =

0

Следовательно векторы компланарны

упражнение 11

>> syms x1 x2 y1 y2 z1 z2

>> a=[x1,y1,z1];b=[x2,y2,z2];

>> c1=x1*x2+y1*y2+z1*z2

c1 =

x1*x2+y1*y2+z1*z2

>> c2=a.*b

c2 =

[ x1*x2, y1*y2, z1*z2]

>> scalar = c2(1) + c2(2) + c2(3)

scalar =

x1*x2+y1*y2+z1*z2

>> scalar = sum(a.*b)

scalar =

x1*x2+y1*y2+z1*z2