Answer:
A is correct.
i.e. the functions:
y=x , y= x^3 , y= int (x)
Step-by-step explanation:
We have to find which of the choice is best such that it satisfy:
lim f(x) = -∞ when x→ -∞.
B)
[y=x, y=1/(1=e^{-x}) , y= int (x)
Now we consider the function y=1/(1+e^{-x}).
We know that when x → -∞
y=f(x)→ 0
since e^{-x} →∞ when x → -∞
and so 1+e^{-x} → ∞
and hence 1/(1+e^{-x}) → 0.
Hence, B option is incorrect.
D)
Similarly D option is also incorrect.( as done in part B)
C)
y=x^2, y=x^3 , y= int (x)
We know that y=x^2 always gives a positive value for any x.
The end behaviour of y=x^2 is that it reaches to ∞.
Hence when x → - ∞ y=x^2 → ∞
Hence, option C is incorrect.
So the options B,C, and D are discarded.
Hence, option: A is correct.
Also it can be observed by there graphs.
