If $\alpha$ and $\beta$ are the roots of the equation 375x² – 25x – 2 = 0, then $\underset{n\to \infty }{\lim }\sum _{r=1}^n{\alpha }^r+\underset{n\to \infty }{\lim }\sum _{r=1}^n{\beta }^r$is equal to :