The function \textsinh(-x) is the hyperbolic sine of the negative of x . It is defined as \textsinh(-x) = \frace^{-x - e^x}2 , where e is the base of the natural logarithm. This function is an odd function, meaning that \textsinh(-x) = -\textsinh(x) . The hyperbolic sine function, \textsinh(x) , is related to the geometry of hyperbolas, similar to how the sine function relates to circles. It is commonly used in various fields, including mathematics, physics, and engineering, particularly in problems involving hyperbolic geometry and wave equations.