Misc
<math>
\begin{align}
&e^{x} - 5 + e^{-x} = 0
&e^{x} - 5 + \frac{1}{e^{x}}=0
&e^{x} (e^{x} - 5 + \frac{1}{e^{x}}) = e^{x} (0)
&e^{2x} - 5e^{x} + 1 = 0
&u^{2} - 5u + 1 = 0 \qquad [u = e^{x}]
&D = (-5)^{2} - 4(1)(1)
&D = 25 - 4 = 21
&u = \frac{-(-5) \pm \sqrt{21}}{2(1)} = \frac{5 \pm \sqrt{21}}{2}
&e^{x} = \frac{5 \pm \sqrt{21}}{2}
&ln(e^{x}) = ln(\frac{5 \pm \sqrt{21}}{2})
&x = \pm 1.5668
</math>
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