Saturday, August 20, 2022

Plus42: The Solver SEQ Command

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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