Some Limits with Maple

> f:=(-x^2+3*x-2)/(x^4+5*x^3+x^2-21*x-18);

> limit(f,x=2);

> limit(f,x=1);

> limit(f,x=0);

> limit(f,x=-3);

> limit(f,x=-1);

> f:=(sqrt(4-h)-sqrt(4))/h;

> limit(f,h=0);

> f:=(sqrt(a-h)-sqrt(a))/h;

> limit(f,h=0);

>