R help - Nov 2010 - Finding root of quadratic equation

Dear R Helpers,

I need to find the root of following equation. 

0.0016^2 = (0.001*x)^2 + (0.002 * (1-x))^2 + 2 * 0.7 *0.001*0.002 * x * (1-x).

I had tried using "animation " package as follows.



# My Code


library(animation)
ani.options(nmax = 500)


solu = newton.method(function(x) 0.0016^2 - 0.001^2*x^2 - 0.002^2*(1-x)^2 -
2*0.7*0.001*0.002*x*(1-x), 1, c(-1,1))

solu$root


# However, I am not getting the solution. Please guide.

Amy







      
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Hi Amy,

Not using animation, but this seems to work:

f <- function(x) 0.0016^2 - 0.001^2*x^2 - 0.002^2*(1-x)^2 -
2*0.7*0.001*0.002*x*(1-x)
curve(f, -1, 1)
abline(h = 0, lty = 2, col = 'gray')
uniroot(f, c(-1,1))
abline(v = .3203, lty = 2, col = 2)

HTH,
Jorge


On Sun, Nov 28, 2010 at 3:43 AM, Amy Milano <> wrote:
> Dear R Helpers,
>
> I need to find the root of following equation.
>
> 0.0016^2 = (0.001*x)^2 + (0.002 * (1-x))^2 + 2 * 0.7 *0.001*0.002 * x *
> (1-x).
>
> I had tried using "animation " package as follows.
>
>
>
> # My Code
>
>
> library(animation)
> ani.options(nmax = 500)
>
>
> solu = newton.method(function(x) 0.0016^2 - 0.001^2*x^2 - 0.002^2*(1-x)^2 -
> 2*0.7*0.001*0.002*x*(1-x), 1, c(-1,1))
>
> solu$root
>
>
> # However, I am not getting the solution. Please guide.
>
> Amy
>
>
>
>
>
>
>
>
>        [[alternative HTML version deleted]]
>
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>
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