Usage: calc [=n] 'expression'
Option: =n  number of digits to compute  
Expression:
  Math operators: + - / * ^ %
  Bool operators: || && !
   Functions:
    sqrt(x)	square root of x
    s(x)	sine of x, x is in radians
    c(x)	cosine of x, x is in radians
    a(x)	arctangent of x, returns radians
    l(x)	natural logarithm of x
    e(x)	exponential function of raising e to the value x
    p           Pi