COSH(x)
COSH function returns the hyperbolic cosine of x, which is defined mathematically as
(exp(x) + exp(-x)) / 2.
COSH(0.5) equals 1.127626.
COSH(1) equals 1.543081.
COS, SIN, SINH, TAN, TANH, RADIANS, DEGREES, EXP.