Section 6: Functions continue96
Logarithmic and Exponential Functions
The HP-41C computes both natural and common logarithms as well as their inverse functions (antilogarithms). The logarithmic functions are: (Notice that the keyboard execution and display execution forms of the natural and common antilog functions are different.)
Natural log   Keyboard and display: LN   Takes the log of the value in the X-register to base e (2.718...).
Natural antilog   Keyboard execution: ex
Display execution: E X
  Raises e (2.718...) to the power of the value in the X-register. Press 1 g ex to display value of e.
Common log   Keyboard and display: LOG   Computes the log of the value in the X-register to base 10.
Common antilog   Keyboard execution: 10x
Display execution: 10 X
  Raises 10 to the power of the value in the X-register.
Natural log
(for arguments close
to one)
  Display execution: LN1+X   Computes ln (1 + X), where X is a number very close to zero. LN1+X provides greater precison than LN when you are finding that the natural log of numbers close to one. Example: To find the natural log of (1 + 4.25 × 10–6, key in 4.25 × 10–6 and execute LN1+X . Answers are displayed in SCI format.
Natural antilog
(for arguments close
to zero)
  Display execution: E X–1   Computes (ex) – 1, where X is a number very close to zero. E X–1 provides greater precison than ex for numbers very close to zero. Example: To calculate (e4:25 × 10–6) – 1, key in 4.25 × 10–6 and execute E X–1 . Answers are displayed in SCI format.