Calculus?

If y = 7 is a horizontal asymptote of a rational function f, then which of the following must be true?

a. lim f(x) = infinity
x- 7

b. lim f(x) = 7
x- infinity

c. lim f(x) = 7
x - 0

d. lim f(x) = 0
x - 7

e. lim f(x) = - 7
x - - infinity

Question

Calculus?

If y = 7 is a horizontal asymptote of a rational function f, then which of the following must be true?

a. lim  f(x) = infinity 
x-> 7 

b. lim  f(x) = 7 
x->  infinity 

c. lim  f(x) = 7 
x -> 0 

d. lim  f(x) = 0 
x -> 7 

e. lim      f(x) = - 7
x -> - infinity

campbell_st · Answer

well here is a diagram that may help 

|dw:1389291466300:dw|

is a very simple case... but where are the x values heading... and whats happening to the curve?