Return the hyperbolic tangent of {expr} as a |Float| in the range [-1, 1]. {expr} must evaluate to a |Float| or a |Number|. Returns 0.0 if {expr} is not a |Float| or a |Number|. Examples: :echo tanh(0.5) 0.462117 :echo tanh(-1) -0.761594 Can also be used as a |method|: Compute()->tanh() {only available when compiled with the |+float| feature}