% NEWTON-RAPHSON ALGORITHM 2.3
%
% To find a solution to f(x) = 0 given an
% initial approximation p0:
%
% INPUT: initial approximation p0; tolerance TOL;
% maximum number of iterations NO.
%
% OUTPUT: approximate solution p or a message of failure
syms('OK', 'P0', 'TOL', 'NO', 'FLAG', 'NAME', 'OUP', 'F0');
syms('I', 'FP0', 'D','x','s');
TRUE = 1;
FALSE = 0;
fprintf(1,'This is Newtons Method\n');
fprintf(1,'Input the function F(x) in terms of x\n');
fprintf(1,'For example: cos(x)\n');
s = input(' ','s');
F = inline(s,'x');
fprintf(1,'Input the derivative of F(x) in terms of x\n');
s = input(' ');
FP = inline(s,'x');
OK = FALSE;
fprintf(1,'Input initial approximation\n');
P0 = input(' ');
while OK == FALSE
fprintf(1,'Input tolerance\n');
TOL = input(' ');
if TOL <= 0
fprintf(1,'Tolerance must be positive\n');
else
OK = TRUE;
end
end
OK = FALSE;
while OK == FALSE
fprintf(1,'Input maximum number of iterations - no decimal point\n');
NO = input(' ');
if NO <= 0
fprintf(1,'Must be positive integer\n');
else
OK = TRUE;
end
end
if OK == TRUE
fprintf(1,'Select output destination\n');
fprintf(1,'1. Screen\n');
fprintf(1,'2. Text file\n');
fprintf(1,'Enter 1 or 2\n');
FLAG = input(' ');
if FLAG == 2
fprintf(1,'Input the file name in the form - drive:\\name.ext\n');
fprintf(1,'For example: A:\\OUTPUT.DTA\n');
NAME = input(' ','s');
OUP = fopen(NAME,'wt');
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