Rational limit involving e?

**nautica17** · January 26th 2010, 08:13 AM

Need some help with this one:

lim x-> inf of (1-e^x) / (1+e^x)

The answer should be -1 but I don't get how that is so. When you plug in infinity you get -inf/inf right? How does this problem work out algebraically?

**Krizalid** · January 26th 2010, 08:17 AM

$\frac{1-e^{x}}{1+e^{x}}=\frac{e^{-x}-1}{e^{-x}+1},$ can you compute its limit now?

**nautica17** · January 26th 2010, 08:21 AM

Originally Posted by Krizalid

$\frac{1-e^{x}}{1+e^{x}}=\frac{e^{-x}-1}{e^{-x}+1},$ can you compute its limit now?

Thank-you! I get it now!

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