initial commit / add all books

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diff --git a/191/CH4/EX4.8/Example4_8.sce b/191/CH4/EX4.8/Example4_8.sce
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+//Gerschgorin's first theorem

+clc;

+clear;

+close();

+//find the eigen values lying [0,4] with an error of 0.25

+//taking p at mid point of the interval

+C=[2,-1,0;-1,2,-1;0,-1,1];

+p=2;

+

+f(1)=1;

+f(2)=C(1,1)-p;

+count = 0;

+if f(1)*f(2)>0 then

+    count = 1;

+end

+for r=3:4

+    br=C(r-2,r-1);

+    f(r)=-br^2*f(r-2)+(C(r-1,r-1)-p)*f(r-1);

+    if f(r)*f(r-1)>0 then

+        count = count+1;

+//    elseif f(r-1)==0 && f(r-1)*        ?????? check for sign when f(r)=zero

+    end

+end

+disp(f,'Sturm sequences')

+disp(count,'Number of eigen values strickly greater than 2 : ')

+

+p=1;

+f(1)=1;

+f(2)=C(1,1)-p;

+count1 = 0;

+if f(1)*f(2)>0 then

+    count1 = 1;

+end

+for r=3:4

+    br=C(r-2,r-1);

+    f(r)=-br^2*f(r-2)+(C(r-1,r-1)-p)*f(r-1);

+    if f(r)*f(r-1)>0 then

+        count1 = count1+1;

+    end

+end

+disp(f,'Sturm sequences')

+disp(count1,'Number of eigen values strickly greater than 1 : ')

+

+p=1.5;

+f(1)=1;

+f(2)=C(1,1)-p;

+count2 = 0;

+if f(1)*f(2)>0 then

+    count2 = 1;

+end

+for r=3:4

+    br=C(r-2,r-1);

+    f(r)=-br^2*f(r-2)+(C(r-1,r-1)-p)*f(r-1);

+    if f(r)*f(r-1)>0 then

+        count2 = count2+1;

+    end

+end

+disp(f,'Sturm sequences')

+disp(count2,'Number of eigen values strickly greater than 1.5 : ')

+disp(p+0.25,'Eigen value lying between [1.5,2] ie with an error of 0.25 is : ')
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