18. The expression (e^2x-e^-2x)/(e^2x)+e^(-2x) is equivalent to __ A. 1 B. sinhx C. sinh2x D. tanh2x

The given expression is \((e^{2x}-e^{-2x})/(e^{2x}+e^{-2x})\). This expression is equivalent to the hyperbolic tangent function, denoted as \(tanh(x)\). Specifically, the expression is equivalent to \(tanh(2x)\). Therefore, the correct answer is option D: .