The function $\cos(x)$ is approximated using Taylor series around $x=0$ as $\cos(x) \approx 1 + ax + bx^2 + cx^3 + dx^4$. The values of  $a,b,c$ and $d$ are
1. $a=1, \: b=-0.5,\: c=-1, \: d=-0.25$
2. $a=0, \: b=-0.5,\: c=0, \: d=0.042$
3. $a=0, \: b=0.5,\: c=0, \: d=0.042$
4. $a=-0.5, \: b=0,\: c=0.042, \: d=0$