How do you find the slant asymptote of ( x^4 + 1 ) / ( x^2 + 2 )x4+1x2+2?

1 Answer
Jan 15, 2016

This rational function is asymptotic to a parabola, not a line.

It has no slant asymptote.

Explanation:

The degree of the numerator is 44 and the degree of the numerator is 22.

As a result this rational function is asymptotic to a parabola, not a line.

More explicitly:

f(x) = (x^4+1)/(x^2+2)f(x)=x4+1x2+2

=(x^4+2x^2-2x^2-4+5)/(x^2+2)=x4+2x22x24+5x2+2

=(x^2(x^2+2)-2(x^2+2)+5)/(x^2+2)=x2(x2+2)2(x2+2)+5x2+2

=x^2-2 + 5/(x^2+2)=x22+5x2+2

So as x->+-oox± we find (f(x) - (x^2-2)) -> 0(f(x)(x22))0

That is f(x)f(x) is asymptotic to x^2-2x22