令x+2=t,则x=t-2,展开成t的幂级数即可
f(x)=1/[(x+2)^2+5]=1/(t^2+5)
=0.2/(1+0.2t^2)
=0.2[1-0.2t^2+(0.2t^2)^2-(0.2t^2)^3+.
=0.2-0.04t^2+0.008t^4-0.0016t^6+.