# newton raphson

• December 17th 2008, 03:54 AM
Parton-Bill
newton raphson
Hi guys, doing this on spread sheets ~ exel.

Using newtons-Raphson method of succesive approximation to determine to 4 decimal places the root of equation 0.25x^2-6sin2x =0 in the region of x = 4.2

If f(x) = 0.25^2-6sin2x

Whats would f'(x) be???

I think maybe f'(x) = 0.50x + 12cos2x ???
• December 17th 2008, 04:23 AM
Newton Raphson
Hi -

Quote:

Originally Posted by Parton-Bill
Hi guys, doing this on spread sheets ~ exel.

Using newtons-Raphson method of succesive approximation to determine to 4 decimal places the root of equation 0.25x^2-6sin2x =0 in the region of x = 4.2

If f(x) = 0.25^2-6sin2x

Whats would f'(x) be???

I think maybe f'(x) = 0.50x + 12cos2x ???

$\frac{d}{dx} (\sin x) = \cos x$

So: $f(x) = 0.25x^2-6sin2x \implies f'(x)=0.50x - 12 \cos2x$