A-level maths question

How do I do:
tanx = 2x using the newton raphson method?

I thought Newton-Raphson is fairly algorithmic? Just follow the steps (from your notes/textbook) and you are there.

Also I assume you don't want the solution x=0 (by inspection).

Showing your incomplete/incorrect work would help us help you.

Reply 2

jiscoff

OP

3

Original post by tonyiptony

I thought Newton-Raphson is fairly algorithmic? Just follow the steps (from your notes/textbook) and you are there.

Also I assume you don't want the solution x=0 (by inspection).

Showing your incomplete/incorrect work would help us help you.

I’m meant to do it graphically but I am struggling as I got x = 0.

Reply 3

tonyiptony

11

Original post by jiscoff

I’m meant to do it graphically but I am struggling as I got x = 0.

The result of Newton-Raphson very much depend on your choice of the first point. So if your first choice doesn't work, find another one (which one? try!).
Did the question ask you which solution are you looking for, because if you sketch the graphs of tan(x) and 2x, you'll get infinitely many solutions...

Reply 4

jiscoff

OP

3

Original post by tonyiptony

The result of Newton-Raphson very much depend on your choice of the first point. So if your first choice doesn't work, find another one (which one? try!).
Did the question ask you which solution are you looking for, because if you sketch the graphs of tan(x) and 2x, you'll get infinitely many solutions...