From 82e6cf7d1046d6cee16f7e8b044ec33e7ec6c4b7 Mon Sep 17 00:00:00 2001 From: Nguyễn Gia Phong Date: Sun, 16 Feb 2020 14:26:55 +0700 Subject: [usth] Numerical Method is MATH2.4 --- usth/MATH2.2/hw/cubic | 25 ------------------------- 1 file changed, 25 deletions(-) delete mode 100755 usth/MATH2.2/hw/cubic (limited to 'usth/MATH2.2/hw/cubic') diff --git a/usth/MATH2.2/hw/cubic b/usth/MATH2.2/hw/cubic deleted file mode 100755 index ca24739..0000000 --- a/usth/MATH2.2/hw/cubic +++ /dev/null @@ -1,25 +0,0 @@ -#!/usr/bin/env octave -disp ("Solve quadratic equation a*x^3 + b*x^2 + c*x + d = 0"); -a = input ("a = "); -while (a == 0) - disp ("a must be nonzero"); - a = input ("a = "); -end -b = input ("b = "); -c = input ("c = "); -d = input ("d = "); - -% Using the trigonometric and hyperbolic solutions on Wikipedia: -% https://en.wikipedia.org/wiki/Cubic_function -p = (3*a*c - b^2) / (3*a^2); -q = (2*b^3 - 9*a*b*c + 27*a^2*d) / (27*a^3); -if (p == 0) - disp ("The given cubic equation has only one distinct solution:"); - x = cbrt(-q) - b/a/3 -else - r = 2 * sqrt(-p/3); - disp ("The three solutions of the given quadratic equation are:"); - for k = 0 : 2 - x = r * cos((acos(3*q/p/r) - 2*pi*k) / 3) - b/a/3 - end -end -- cgit 1.4.1