HYPERBOLIC FUNCTIONS: Prove the stated property of the hyperbolic functions. tanh (x + y) = tanh x+tanh y 1 +tanh x tanh y csch2x = coth2x - 1 sech'x = 1 - tanh~x MAXIMA/MINIMA: Locate the critical points and determine the maxima and minima by the tests. y= x - 3x- +4x + 5 By = x' (2al - x2) y= -4(x + 2)2 y = 4x2 + 16x +9 9aBy = x(4a - x)3