Identify the function whose Maclaurin series is ∑n=0∞(−1)nx2n(2n)!\sum_{n=0}^{\infty} \frac{(-1)^n x^{2n}}{(2n)!}∑n=0∞(2n)!(−1)nx2n.
sin(x)\sin(x)sin(x)
cos(x)\cos(x)cos(x)
sin(x2)\sin(x^2)sin(x2)
e−x2e^{-x^2}e−x2