What is the third non-zero term of the Taylor series for f(x)=cos(x)f(x) = \cos(\sqrt{x})f(x)=cos(x) centered at a=0a=0a=0?
x2/24x^2/24x2/24
x2/120x^2/120x2/120
x3/720x^3/720x3/720
x2/720x^2/720x2/720