Math Is Fun Forum

Raabi

Member

Registered: 2012-11-22

Posts: 18

Regula Falsi method Formulae

Hello Wizards

This time, I came up with another confusion on the subject. Just over-viewing the subject, I found two entirely different (apparently, at least) formulae for the method. One is:

x1 = [a * f(b) - b*f(a)] / [f(b) - f(a)]; where a and b are two guess points.

The other is:

x = [xn - x(n-1)] / [f((xn) - f(xn-1)] * f(xn)

Are these two formulae actually the same or different for their use in different situations. Please help keeping in mind that I am just a toddler in this branch of mathematics.

I hope and wish bobbym is somewhere around.

Thanks in anticipation.

Raabi

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Regula Falsi method Formulae

Hi;

The first one I recognize as the false position method.

The second one is slightly off.

No matter how it is phrased it is not my favorite choice for obtaining roots.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Raabi

Member

Registered: 2012-11-22

Posts: 18

Re: Regula Falsi method Formulae

ok, thanks and regards.

Raabi

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Regula Falsi method Formulae

Hi;

There is also if I remember a slight difference between the secant method and regula falsi.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Raabi

Member

Registered: 2012-11-22

Posts: 18

Re: Regula Falsi method Formulae

Well, let me explore Secant method, and thanks again for your attention.