Which of the following series represents the function f(x)=cos(x2)f(x) = \cos(x^2)f(x)=cos(x2)?
∑n=0∞(−1)nxn+2(2n)!\sum_{n=0}^{\infty} \frac{(-1)^n x^{n+2}}{(2n)!}∑n=0∞(2n)!(−1)nxn+2
∑n=0∞(−1)nx2n(2n)!\sum_{n=0}^{\infty} \frac{(-1)^n x^{2n}}{(2n)!}∑n=0∞(2n)!(−1)nx2n
∑n=0∞(−1)nx4n(2n)!\sum_{n=0}^{\infty} \frac{(-1)^n x^{4n}}{(2n)!}∑n=0∞(2n)!(−1)nx4n
∑n=0∞(−1)nx2n+2(2n)!\sum_{n=0}^{\infty} \frac{(-1)^n x^{2n+2}}{(2n)!}∑n=0∞(2n)!(−1)nx2n+2