## Using Solve( in basic

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**1**of**1**- hayzel
- Member
**Posts:**43**Joined:**Thu May 31, 2012 5:45 pm**Location:**Greece**Calculators:**Casio fx-9860 G SD

### Using Solve( in basic

Is there a way to use the builtin Solve( in my casio basic program ?

I want to solve a simple polynomial equation of the form:

A X^3+ B X^2 + C X + D =0

A simple code example would be great:

1->A

-2->B

-3->C

5->D

Solve( ?????

I want to solve a simple polynomial equation of the form:

A X^3+ B X^2 + C X + D =0

A simple code example would be great:

1->A

-2->B

-3->C

5->D

Solve( ?????

- aapman55
- Senior Member
**Posts:**66**Joined:**Sun Apr 15, 2012 4:00 pm**Calculators:**Casio fx-9860G

if you have the equation 3X^2+2X-3=5 and you would like to determine the x values.

then you can write

with 0 the initial value. As this equations has 2 solutions be carefull how you choose the initial value. f.i. if you choose the initial value to be -20, the answer will be -2 and if you choose it to be 0 it gives you 1.33333.

If you have used matlab, it is comparable to what you do with fzero, where you also need to "guess" the right initial.

then you can write

- Code: Select all
`Solve(3X^2+2X-3=5,0)`

with 0 the initial value. As this equations has 2 solutions be carefull how you choose the initial value. f.i. if you choose the initial value to be -20, the answer will be -2 and if you choose it to be 0 it gives you 1.33333.

If you have used matlab, it is comparable to what you do with fzero, where you also need to "guess" the right initial.

hayzel wrote:Is there a way to use the builtin Solve( in my casio basic program ?

I want to solve a simple polynomial equation of the form:

A X^3+ B X^2 + C X + D =0

A simple code example would be great:

1->A

-2->B

-3->C

5->D

Solve( ?????

- Code: Select all
`1->A`

-2->B

-3->C

5->D

Solve(AX^3+BX^2+CX+D,X,0)

- hayzel
- Member
**Posts:**43**Joined:**Thu May 31, 2012 5:45 pm**Location:**Greece**Calculators:**Casio fx-9860 G SD

Doesn't help. I was hoping something like the polynomial solver inside EQUA, that gives all the solutions.

I wanted all the three solutions.

I found a trig formula to solve the cubic function for only real solutions. So I used that.

Thanks.

I wanted all the three solutions.

I found a trig formula to solve the cubic function for only real solutions. So I used that.

Thanks.

- Code: Select all
`ClrText`

"Entrez l'equation"?->[b]Y[/b]1

1ÞDim List 1

ClrText

Locate 1,1,"Resolution en cours.."

Locate 3,3,"[- ]"

1->D

0->Q

Locate 5,3,"-"

Abs Int Solve([b]Y[/b]1,-10^6)->A

Locate 6,3,"--"

Int A/10->S

Locate 7,3,"-"

For -A->C To A Step S

Solve([b]Y[/b]1,C)->R

Locate 8+Int (10(C+A)/2A),3,"-"

If R-Qâ10^-9 Or Not Q

Then R->Q

R->List 1[D]

Isz D

IfEnd

Next

The solution are in List 1

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