8 files changed, 96 insertions, 0 deletions
diff --git a/70/CH6/EX6.1.1/6_1_1.sci b/70/CH6/EX6.1.1/6_1_1.sci
new file mode 100755
index 000000000..d9fddf923
--- /dev/null
+++ b/70/CH6/EX6.1.1/6_1_1.sci
@@ -0,0 +1,11 @@
+//313
+clear;
+close;
+clc;
+disp('f(x,y)=x^2-10*x*y+y^2');
+a=1;
+c=1;
+deff('[f]=f(x,y)','f=x^2-10*x*y+y^2');
+disp(f(1,1),'f(1,1)=');
+disp('The conditions a>0 and c>0 ensure that f(x,y) is positive on the x and y axes. But this function is negative on the line x=y,because b=-10 overwhelms a and c. ');
+//end
+\ No newline at end of file
diff --git a/70/CH6/EX6.1.3/6_1_3.sci b/70/CH6/EX6.1.3/6_1_3.sci
new file mode 100755
index 000000000..3a53a4b06
--- /dev/null
+++ b/70/CH6/EX6.1.3/6_1_3.sci
@@ -0,0 +1,12 @@
+//315
+clear;
+close;
+clc;
+disp('f(x,y)=2*x^2+4*x*y+y^2');
+A=[2 2;2 1];
+a=1;
+c=1;
+b=2;
+disp(a*c,'ac=');
+disp(b^2,'b^2=');
+disp('Saddle point,as ac<b^2');
diff --git a/70/CH6/EX6.1.4/6_1_4.sci b/70/CH6/EX6.1.4/6_1_4.sci
new file mode 100755
index 000000000..d187b1e7d
--- /dev/null
+++ b/70/CH6/EX6.1.4/6_1_4.sci
@@ -0,0 +1,12 @@
+//315
+clear;
+close;
+clc;
+disp('f(x,y)=2*x^2+4*x*y+y^2');
+A=[2 2;2 1];
+a=0;
+c=0;
+b=1;
+disp(a*c,'ac=');
+disp(b^2,'b^2=');
+disp('Saddle point,as ac<b^2');
+\ No newline at end of file
diff --git a/70/CH6/EX6.2.2/6_1_2.sci b/70/CH6/EX6.2.2/6_1_2.sci
new file mode 100755
index 000000000..1ed56b13d
--- /dev/null
+++ b/70/CH6/EX6.2.2/6_1_2.sci
@@ -0,0 +1,11 @@
+//313
+clear;
+close;
+clc;
+disp('f(x,y)=x^2+4*x*y+y^2');
+a=1;
+c=1;
+deff('[f]=f(x,y)','f=x^2+4*x*y+y^2');
+disp(f(0,0),'f(0,0)=')
+disp('Here 2b=4  it still does not ensure a minimum ,the sign of b is of no importance.Neither F nor f has a minimum at(0,0) because f(1,-1)=-1.')
+//end
+\ No newline at end of file
diff --git a/70/CH6/EX6.3.1/6_3_1.sci b/70/CH6/EX6.3.1/6_3_1.sci
new file mode 100755
index 000000000..68e83af1c
--- /dev/null
+++ b/70/CH6/EX6.3.1/6_3_1.sci
@@ -0,0 +1,12 @@
+//332
+clear;
+close;
+clc;
+A=[-1 2 2]';
+disp(A,'A=');
+[U diagnol V]=svd(A);
+disp(U,'U=');
+disp(diagnol,'diagnol=');
+disp(V','V''=');
+disp(U*diagnol*V','A=U*diagnol*V''')
+//end
+\ No newline at end of file
diff --git a/70/CH6/EX6.3.2/6_3_2.sci b/70/CH6/EX6.3.2/6_3_2.sci
new file mode 100755
index 000000000..112a5f735
--- /dev/null
+++ b/70/CH6/EX6.3.2/6_3_2.sci
@@ -0,0 +1,12 @@
+//332
+clear;
+close;
+clc;
+A=[-1 1 0;0 -1 1];
+disp(A,'A=');
+[U diagnl V]=svd(A);
+disp(U,'U=');
+disp(diagnl,'Diagonal=');
+disp(V','V''=');
+disp(U*diagnl*V','A=U*diagonal*V''=')
+//end
+\ No newline at end of file
diff --git a/70/CH6/EX6.3.3/6_3_3.sci b/70/CH6/EX6.3.3/6_3_3.sci
new file mode 100755
index 000000000..8538eac4d
--- /dev/null
+++ b/70/CH6/EX6.3.3/6_3_3.sci
@@ -0,0 +1,13 @@
+//332
+clear;
+close;
+clc;
+A=[1 -2;3 -1];
+disp(A,'A=');
+[U S V]=svd(A);
+Q=U*V';
+S=V*S*V';
+disp(Q,'Q=');
+disp(S,'S=');
+disp(Q*S,'A=SQ=')
+//end
+\ No newline at end of file
diff --git a/70/CH6/EX6.3.4/6_3_4.sci b/70/CH6/EX6.3.4/6_3_4.sci
new file mode 100755
index 000000000..3e4128817
--- /dev/null
+++ b/70/CH6/EX6.3.4/6_3_4.sci
@@ -0,0 +1,13 @@
+//332
+clear;
+close;
+clc;
+A=[1 -2;3 -1];
+disp(A,'A=');
+[U diag1 V]=svd(A);
+Q=U*V';
+S=[2 1;1 3];
+disp(Q,'Q=');
+disp(S,'S=')
+disp(S'*Q,'A=S''Q=')
+//end