HP 49g Graphing Calculator - Manual (Page 72)

Conversions between the four temperature scales (K, °C, °F, and °R)
involve additive constants as well as multiplicative factors. The additive
constants are included in a conversion when the temperatiue units reflect
actual temperature levels, and are ignored when the temperature units
reflect temperature differences.
•
Pure temperature units (levels). If both unit expressions consist of
a single, unpreflxed temperature unit with no exponent, the
CONVERT
command performs an absolute temperature scale conversion which
includes the additive constants.
• Combined temperature units (differences). If either unit
expression includes a prefix, an exponent, or any unit other tiran a
temperature unit, the
CONVERT
command perfonns a relative
temperature unit conversion which ignores the additive constants.
The two examples below illustrate these differences.
Example 1: Convert 25°C to °F.
1. Press 0 íDÑÍTS)
TOOLS CONVERT.
2. Enter 25„°C.
3. Press 0Q.
4. Enter L°F.
It does not matter what value you give to the number part of this unit
object.
5. Press (Em).
The answer is 77 °F.
Converting temperature units
In RPN mode: follow steps 2, 4, and 1.
Unit objects Page 6-9