Input Programs for Fx 3650P / Fx3950P / Fx50FH (S4)
Solve Cubic Equations
Solve ax3 +bx2 + cx + d = 0
For input of this program, there are special functions (in purple colour), press shift before the button for the function
[Abs, ∠, arg]
For “ ° ”, press button ° ‘ “
Input (3650P / 3950P)
Mode 2
Mode Mode Mode 1 3
?→A:?→B:?→C:?→M:
B ÷ 3A → B :
3
x
(BC – M) ÷ 2A – B + 10 (-) 99 → M :
C ÷ 3A – B2 → A :
M2 + A3 :
√Ans “M+” :
3
0 → C : Lbl 1 :
√ Abs M ∠ (C + 3 –1 arg M :
Ans – B – A ÷ (Ans + 10x (-) 99 
C + 120° → C :
C ≠ 360° ⇒ Goto 1 : 0
Mode Mode Mode 2
Mode 1
(116 steps)
Input (50FH)
Mode Mode 6 1 3 1
?→A:?→B:?→C:?→D:
(-) B ÷ ( 3A → B :
3
B – (BC + D) ÷ (2A → D :
B2 – C ÷ (3A → C :
2
3
D –C →X:
X ≤ 0 ⇒ Goto 1 :
3
D + √( X :
√( Ans ) + B – 3√( Ans – 2D
0 –1 : Lbl 1 : C ⇒ 3–1 cos–1 ( D ÷ √( C3 → X : B + 2 √( C) cos( X 
B + 2 √( C ) cos( X – 120 ° 
B + 2 √( C ) cos ( X + 120 °
Mode 1
(139 steps) [Note: ° : Press “shift” “Ans” “1”]
Use of program
1) Solve x3 + 3x2 – 2x – 1 = 0
Input
1
EXE
3
EXE
(-) 2
EXE
(-) 1
Show
0.834
-3.491
-0.343 (solutions of x)

EXE
Important: Press “Mode 1” after using the program
2) Solve x3 – 3x2 + 2x + 1 = 0
Input
1
EXE
(-) 3
EXE
2
EXE
1
EXE
FX 3650P / 3950P:
Show
1.662 (Note: There is “Re⇔Im” Shown, the root is not real number, ignore this root)
-0.325 (No “Re⇔Im” shown, this is a real root)
1.662 (“Re⇔Im” shown, ignore this root)
i.e. Solution x = -0.325 only
Note: For equation in x3, there will be one real root or three real roots, including double roots. It is
impossible that there are two real roots.
FX50FH:
Show –0.325, Math Error
i.e. root is –0.325 only