Vertical, Horizontal, and Slant Asymptotes – (continued)

 

The line  y  =  mx + b  is a slant asymptote of the curve   y =  f(x)  provided that either

 

               lim [f(x) – (mx + b)]  =  0  

             x→ +∞        

 or 

                               

             lim [f(x) – (mx + b)]  =  0  

             x→˗ ∞

 

               

 

   

Slant asymptotes may occur when you have a ratio of polynomials.  i.e.

 

Suppose  f(x)  =  p(x)/q(x)  where p(x) is 1 degree larger than q(x).

 

Then long division yields:             f(x)  =  mx + b  +  g(x)

 

where m ≠ 0  and if       lim g(x)  =  0     y  =  f(x) =  mx + b       is a slant asymptote.

                                     x→ ± ∞        

 

Click here for examples.

 


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