Hmm. Why does this feel like deja vu? (Answer: I just answered almost the same question for someone else, not 5 minutes ago.)
d = @(g)1-5*g-2.5*g.^2+6*g.^3+5*g.^4;
e = -2:1/100:2;
It looks fine to me. Whats the problem? That two programs arbitrarily chose a different set of axes to plot the same curve?
Same curve. Same plot. Very different conclusions, just by changing the axis scaling.