Plus42: The Solver SEQ Command
Solver SEQ Function
In the calculator app Plus42, we can evaluate a sequence of calculations to return a result. The SEQ is also good for the FOR loop because it allows us to initialize several variables.
Syntax:
SEQ( expr1 : expr2 : expr3: ... : expr_n )
I think this is best illustrated by example.
Example 1
Calculate f(x) = x * p ÷ t^2
where:
p = 0.01 * a^2
a = 36 *t^2 - 280
Equation:
SEQ1:F=SEQ(L(A:36×T^2-280):L(P:.01×G(A)^2))×X÷EXP(T)
The commands listed in the SEQ are:
1. L(A:36×T^2-280): Let A = 36 * T^2 - 280. T is the input variable.
2. L(P:.01×G(A)^2)): Let P = 0.01 * A^2; the Get command (G) is used to keep A from the variable menu
The answer is stored in P.
Variables in calculation: F, T, X
X = 2, T = 0.8, solve for F = 593.3698253
X = 0.3, T = 9, solve for F = 2.57253759
T = 11.1, F = 58.68, solve for X = 22.4853545434
Example 2
Calculate p = Π( n / 4, n = 1 to m)
Equation:
SEQ2: P=FOR(SEQ(L(A:1):L(N:1)):G(N)<=IP(M):L(N:G(N)+1):L(A:G(A)×(G(N)÷4)))
The commands listed in the SEQ are:
1. L(A:1): Let A = 1
2. L(N:1): Let N = 1
In this example, SEQ is in a FOR command and is used to initialize variables.
Variables in calculation: M, P
M = 3, solve for P = 0.09375
M = 6, solve for P = 0.17578125
M = 18, solve for P = 93166.79943
If you have not checked out the Plus42 app, please check it out. The Plus42 is an HP-42S Simulator which builds up on the Free42. However, the Plus42 adds the solver in a style of the HP 17B and 27S, graphing commands, and units.
Thomas Okken's Plus42 page: https://www.thomasokken.com/plus42/
Note: Casio fx-991EX Week - September 5, 2022 to September 9, 2022
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