[R] How to solve this complex equation

[S Ellison]

> -----Original Message-----
> I want to use R to calculate the variable x which is in a complex equation in
> below:
> 
>  2
>  Σ[exp(-x/2)*(x^k)/(2^k*k!)]=0.05
> k=0
> 
> how to solve this equation to get the exact x in R?

For a _numerical_ solution, if f(x) is your function, use uniroot to find a root of (f(x) - 0.05) 
That will normally need you to define a new function g(x) = f(x)-0.05 and apply uniroot to g(x)


S Ellison




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