why is there an oblique asymptote at y = 1 for this curve ?

Question

y = (1 - 2^x) / (1 + 2^x)

i only found one at y = -1 but there's suppose to be one at y = 1 as well according to the answer. however if i simply divide top and bottom by 2^x as usually, i can only get the -1 part. can someone show me

Sorry, not oblique i mean horizontal asymptote!!!

Answer 1

y = (1 - 2^x) / (1 + 2^x)

Limit x→ ∞ of {(1 - 2^x) / (1 + 2^x)}
= Limit x→ ∞ of {-2^x / 2^x} = -1

But

Limit x→ -∞ of {(1 - 2^x) / (1 + 2^x)}
= Limit x→ -∞ of {(1 - 0) / (1 + 0)} = 1/1 = 1

Answer 2

as x tends to +infinity, y tends to -1
as x tends to -infinity, y tends to +1

there are your asymptotes

(drawing a cartesian graph always helps btw)

Answer 3

sdf