HP 33s - Manual (Page 115)

Solving Equations 7–5
g
#O
/
)

 Stores 297.1 in T; solves
for P in atmospheres.
A 5–liter flask contains nitrogen gas. The pressure is 0.05 atmospheres when the
temperature is 18°C. Calculate the density of the gas (N
× 28/V, where 28 is the
molecular weight of nitrogen).
Keys: Display: Description:
| H
º#/º º! Displays the equation.
 N @
)

 Solves for N; prompts for
P.
.05 g
#@
)
 Stores .05 in P; prompts
for V.
5 g
@
)
 Stores 5 in V; prompts for
R
.
g
!@

)
 Retains previous R;
prompts for T.
18 ‘ 273.1 ›
!@
 )
 Calculates T (Kelvins).
g
#
/
)

 Stores 291.1 in T; solves
for N.
28 z
)   Calculates mass in
grams, N
× 28.
L V q
)
  Calculates density in
grams per liter.
Understanding and Controlling SOLVE
SOLVE first attempts to solve the equation directly for the unknown variable. If the
attempt fails, SOLVE changes to an iterative(repetitive) procedure. The procedure
starts by evaluating the equation using two initial guesses for the unknown variable.
Based on the results with those two guesses, SOLVE generates another, better
guess. Through successive iterations, SOLVE finds a value for the unknown that
makes the value of the equation equal to zero.