pi     = atan(1)*4              ;  3.14159265358979324
e      = exp(1)                 ;  Natural log constant (2.71828182845904524)
h      = 6.62607540E-34         ;  Planck's constant (J s)

sec(x) = 1 / cos(x)             ;  Secant
csc(x) = 1 / sin(x)             ;  Cosecant
cot(x) = cos(x) / sin(x)        ;  Cotangent