HP 35s Scientific Calculator - Manual (Page 119)

Entering and Evaluating Equations 6-17
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Eight of the equation functions have names that differ from their equivalent
operations:
Example: Perimeter of a Trapezoid.
The following equation calculates the perimeter of a trapezoid. This is how the
equation might appear in a book:
Perimeter = a + b + h ( )
The following equation obeys the syntax rules for HP 35s equations:
RPN Operation Equation function
x 2 SQ
SQRT
e x EXP
10 x ALOG
1/x INV
XROOT
y x ^
INT÷ IDIV
x
X y
φ θ
sin
1
sin
1 +
b
a
h
φ
θ