Could you please explain these questions to me in step by step format? I am clearly struggling with series.

X 3. Which of the following series converge? O none of these series converges O 2k-1 1 O more than one of the series listed here converges O (sink' + 1) X O 13. If f(x) = EN, (cos x)", then for what value(s) of x does / have a finite value?10. For the series approximation for sin x = 1 21 + . what is the minimum number of terms needed to approximate sin 0.5 accurate to 3 decimal places