Greates Common Divisor as Linear Combination finder with steps for TI Calculators

GCDLIN.8xp

GCDLIN.8xp.utf8

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Disp "ax + by = c"
Input "a = ",A
Input "b = ",B
Input "c = ",C

If gcd(A,B)≠C
Then
Disp "","Error: c ≠ gcd(a,b)"
Stop
End

{A,B}→L₁
{1,0}→L₂ 
{0,1}→L₃

1→I
While L₁(dim(L₁))
I+1→I
int(L₁(I-1)/L₁(I))→Q
If L₁(I-1)-Ans*L₁(I)=0
Then
Goto A
End
L₁(I-1)-Ans*L₁(I)→L₁(I+1)
L₂(I-1)-Q*L₂(I)→L₂(I+1)
L₃(I-1)-Q*L₃(I)→L₃(I+1)
End

Lbl A
Disp "","x = ",L₂(dim(L₂))
Disp "y = ",L₃(dim(L₃))

L₃→L₄
L₂→L₃
0→L₂(dim(L₁))
For(I,2,dim(L₁))
L₁(I)→L₂(I-1)
End

For(I,2,dim(L₄))
L₃(I)→L₅(I-1)
L₄(I)→L₆(I-1)
End

Disp "","Press 'stat' - 'Edit...'","to see the steps table."
Stop

Preview.png