Solving Newton's Method for f(x) = 0: Step-by-Step

EL ALEM
Messages
25
Reaction score
0

Homework Statement


Nother Q for today:
Let f(x)= (1/x)^x - x
(a)show that f(x)=0 has a solution
(b)show that there is only one solution to f(x)=0
(c)use Newton's Method to find the second approximation x2 of the solution to f(x) =
0 using the initial approximation x1 = 1/2


Homework Equations





The Attempt at a Solution


I know how to do part C just need a little kick in the right direction for the first part.

(1/x)^x - x = 0
(1/x)^x = x
xln(1/x) = lnx
 
Last edited:
Physics news on Phys.org
EL ALEM said:
x \log(1/x) = \log(x)

Remember what \log(a/b) equals to? Break the pieces out.
 
How about the simple fact that 1 to any power is 1?
 
I already got it, it was late and I wasn't thinking straight, thanks for the replies though.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
Back
Top