`sum _(n=0)^oo (x+1)^n/(n!)`

To determine the interval of convergence, use Ratio Test. The formula in Ratio Test is:

`L = lim_(n->oo) |a_(n+1)/a_n|`

If L<1, the series is absolutely convergent.

If L>1, the series is divergent.

And if L=1, the test is inconclusive. The series may converge or diverge.

Applying the formula above, the value of L will be:

`L= lim_(n->oo) |((x+1)^(n+1)/((n+1)!))/((x+1)^n/(n!))|`

`L=lim_(n->oo) | (x+1)^(n+1)/((n+1)!)*(n!)/(x+1)^n|`

`L= lim_(n->oo) | (x+1)^(n+1)/((n+1)n!) *(n!)/(x+1)^n|`

`L = lim_(n->oo) | (x+1)/(n+1)|`

`L= (x+1) lim_(n->oo) |1/(n+1)|`

`L=(x+1) * 0`

`L=0`

Since the value of L is less than 1, the given series converges for all values of x.

**Therefore, the interval of convergence is `(-oo, oo)`
.**

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