Thomas Dean

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These are answers submitted by Thomas Dean

Tom Dean

eqs:=solve({fS,fV,fC,fR},{x1,x2,x3,x4},explicit); # No RootOfs


The problem, as stated involved floating point values and associated errors.

In calculating the target position, an approximation was used.  The values obtained gave different slopes for the bearing lines.

Correcting the calculation of the slopes of the bearing line resulted in a better solution, to several decimal places.

Sorry for the noise.

Tom Dean

help pdsolve[boundaryconditions] has an example that, on the surface, looks sililar.



S := {W,X,Y};

S minus {X};


Tom Dean


## Note:  Here, you are assigning a value to q.
q := -k*(T2-T1)/t;
S := {T1 = 550*Unit('K'), T2 = 50*Unit(Unit('K')), k = 19.1*Unit('W')/(Unit('m')*Unit('K')), t = 2*Unit('cm')};
eval(q, S);

## Note:  At this point, q still has the value assigned above.
##        Maple simplifies the input and the result is t = t!
t := -k*(T2-T1)/q;

S := {T1 = 550*Unit('K'), T2 = 50*Unit(Unit('K')), k = 19.1*Unit('W')/(Unit('m')*Unit('K')), q = 477.5*Unit('kW'/'m'^2)};
eval(t, S);

## Note:  If you avoid using variables that already have values
##        the result is different.  I used zz rather than q to make
##        the name more obvoius.
##        use variable names that make sense in the application.

t := -k*(T2-T1)/zz;

S := {T1 = 550*Unit('K'), T2 = 50*Unit(Unit('K')), k = 19.1*Unit('W')/(Unit('m')*Unit('K')), zz = 477.5*Unit('kW'/'m'^2)};
eval(t, S);

## the same applies to the remainder of your code.

q := 'q';  ## clear the previous value assigned to q.

Tom Dean

Use a function and map



The correct syntax depends on where the file is actually located.  Most likely, if it is a file you created, it will be in some form like

read "/home/<username>/Desktop/code.txt"

Where <username> is the login name of the user.

To get some idea of the equation form, try:

eq1 := {4*x+3*y+z = 0, x+y-z-15 = 0};
eq2 := {9*x+y-3*z-5 = 0, 12*x+5*y+7*z-13 = 0};
plane(P1, eq1[1], [x, y, z]);
plane(P2, eq1[2], [x, y, z]);
plane(P3, eq2[1], [x, y, z]);
plane(P4, eq2[2], [x, y, z]);
intersection(L1, P1, P2);
intersection(L2, P3, P4);

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