429,384 Members | 714 Online
Need help? Post your question and get tips & solutions from a community of 429,384 IT Pros & Developers. It's quick & easy.

# False position method problem

 P: 11 I just want to ask if there is no sign change how can i solve it? my problem is: sinx + cos(1 + x^2) -1 Xi=3 Xi-1= 1 I tried solving it first manually before making a program of it.. Aug 9 '07 #1
5 Replies

 P: 84 I just want to ask if there is no sign change how can i solve it? my problem is: sinx + cos(1 + x^2) -1 Xi=3 Xi-1= 1 I tried solving it first manually before making a program of it.. what are the equations you want to solve (i.e. sin(x)+cos(1+x^2)-1 =????) ? What is the relation between x and Xi? Aug 9 '07 #2

 Expert Mod 100+ P: 931 I just want to ask if there is no sign change how can i solve it? my problem is: sinx + cos(1 + x^2) -1 Xi=3 Xi-1= 1 I tried solving it first manually before making a program of it.. Hi, You want to put the values of x in sinx + cos(1 + x^2) -1 equation to get answer? Kindly elaborate your problem as the information given in your post is not enough to solve your problem. Regards Aug 9 '07 #3

 Expert 10K+ P: 11,448 Hi, You want to put the values of x in sinx + cos(1 + x^2) -1 equation to get answer? Kindly elaborate your problem as the information given in your post is not enough to solve your problem. Regards I recognize that equation; most likely the OP wants to find an approximation of a root of that equation. Using the secant method you need two initial approximations one for which f(x1) < 0 and one for which f(x2) > 0. I think the question is: what to do when the sign of both those function values are equal? I'd say: you can't use that method then. kind regards, Jos Aug 9 '07 #4

 P: 11 thx josh. so can i just say "root can't be solved"? the max iterations for secant method is 4times to get the 1st postive root. can i just change the number of iterations ? Aug 10 '07 #5

 Expert 10K+ P: 11,448 thx josh. so can i just say "root can't be solved"? the max iterations for secant method is 4times to get the 1st postive root. can i just change the number of iterations ? Since the signs of the function values of both Xi and Xi-1 are equal you can't use those two values as initial approximations for the root value; at least you can't use the secant method here. That's all there is to it. You either have to find two other Xi, Xi-1 values or you have to use another approximation method. kind regards, Jos Aug 10 '07 #6