6.59.6  Numeric evaluation: evalf

The evalf command finds floating point approximations to the numbers in an expression or a matrix (see also Section 6.8.1).

• evalf takes one mandatory and one optional argument:
  • expr, an expression or a matrix.
  • Optionally, n, a positive integer representing the significant digits (by default DIGITS, which itself has a default value of 12; see Section 3.5.1).
• evalf(expr ⟨ n ⟩) returns expr with all the numbers replaced by floating point approximations to n digits.

Examples.

• Input:
  evalf(sqrt(2))
  Output:

  1.41421356237

• Input:
  evalf(sqrt(2),20)
  Output:

  1.4142135623730950488

• Input:
  evalf([[1,sqrt(2)],[0,1]])
  Output:

  ⎡ ⎢ ⎣

  1.0 1.41421356237 0.0 1.0

  ⎤ ⎥ ⎦