Nuclei of a radioactive element are being produced at a constant rate α. The element has a decay constant λ. At time t = 0, there are N0 nuclei of the element.
If α=2N0λ, the number N of nuclei as t →∞ is
2N0
If α=2N0λ, then we have
n=1λ[2N0λ−(2N0λ−λN0)e−λt]
=N0(2−e−λt)
When t →∞
N=N0(2−e−)=N0(2−0)=2N0