initial commit / add all books

1 files changed, 20 insertions, 0 deletions

diff --git a/964/CH25/EX25.3/25_3.sce b/964/CH25/EX25.3/25_3.sce
new file mode 100755
index 000000000..7cf519d87
--- /dev/null
+++ b/964/CH25/EX25.3/25_3.sce
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+//clc()

+//dy/dx = -2*x^3 + 12*x^2 - 20*x + 8.5

+//therefore, y = -0.5*x^4 + 4*x^3 - 10*x^2 + 8.5 + c

+x1 = 0;

+y1 = 1;

+h = 0.25;

+c =-(-0.5*x1^4 + 4*x1^3 - 10*x1^2 + 8.5*x1 - y1);

+x = 0:h:4;

+disp(x,"x = ")

+y = -0.5*x^4 + 4*x^3 - 10*x^2 + 8.5*x + c;

+disp(y,"true values of y = ")

+fxy = -2*x^3 + 12*x^2 - 20*x + 8.5;

+y2(1) = y(1);

+e(1) = (y(1) - y2(1)) * 100 / y(1);

+for i = 2:17

+    y2(i) = y2(i-1) + fxy(i-1)*h;

+    e(i) = (y(i) - y2(i))*100/y(i);

+end

+disp(y2,"y by euler method =")

+disp(e,"error =")