root of a quadratic equation

08222015, 09:41 AM
(This post was last modified: 08222015 06:18 PM by tigger.)
Post: #1




root of a quadratic equation
These two equations help to solve a root of a quadratic equation:
<< 2 >LIST SWAP / EVAL SWAP 2 / DUP SQ ROT  v/ DUP2 + ROT ROT  >> << 3 PICK / SWAP ROT 2 * / DUP SQ ROT  SQRT DUP2 * ROT ROT  >> [quote='tigger' pid='40913' dateline='1440236517'] << 2 >LIST SWAP / EVAL SWAP 2 / DUP SQ ROT  v/ DUP2 + ROT ROT  >> The calculator put a blank between the  and the 2 automatically. This could have been the mistake in the program. << 2 >LIST SWAP / EVAL SWAP  2 / DUP SQ ROT  v/ DUP2 + ROT ROT  >> << 3 PICK / SWAP ROT 2 * / DUP SQ ROT  SQRT DUP2 * ROT ROT  >> Is there a sign for SQRT on this page? When I punched the keys in the calculator itself made a blank between the  and the 2. How could I know that the calculator made this mistake? Does the HP always makes mistakes like this? How can I avoid this kind of mistakes? There might be any hope and help to rectify these short programs? 

08222015, 12:03 PM
Post: #2




RE: root of a quadratic equation
Why not using PROOT?
Code: \<< { 3 } \>ARRY PROOT OBJ\> DROP \>> Cheers Thomas 

08222015, 05:17 PM
Post: #3




RE: root of a quadratic equation
When I type the first "\" before << I get "Invalid Syntax".
Without the first "\" I get: Error "Can't find Selection. Could you write me what I did wrong? 

08222015, 06:55 PM
Post: #4




RE: root of a quadratic equation
e.g. for x^2+3x+1=0
input: 1 3 1 << 3 →ARRY PROOT OBJ→ DROP >> EVAL output: 1: .302775637732 2: 3.30277563773 

08222015, 07:01 PM
Post: #5




RE: root of a quadratic equation
I was using trigraphs to write the code. This makes it easy to transfer it to the calculator.
HTH Thomas 

08222015, 07:28 PM
Post: #6




RE: root of a quadratic equation
(08222015 12:03 PM)Thomas Klemm Wrote: Why not using PROOT? Well, for this example PROOT will give ugly approximations: 1 '√2√3' '√6' « { 3 } →ARRY PROOT OBJ→ DROP » EVAL > 1.41421356237 1.73205080757 For exact results, in exact mode I would prefer something like « ROT NEG SWAP OVER / UNROT / 2 / SWAP OVER SQ + √ DUP2  FACTOR UNROT + FACTOR » > '√2' '√3' Cheers, Gerson. 

08222015, 07:33 PM
(This post was last modified: 08222015 07:37 PM by Gerson W. Barbosa.)
Post: #7




RE: root of a quadratic equation
(08222015 09:41 AM)tigger Wrote: There might be any hope and help to rectify these short programs? While these aren't fixed, you can try « ROT NEG SWAP OVER / UNROT / 2. / SWAP OVER SQ + √ DUP2  UNROT + » Not sure whether this is shorter, though. Sizewise, Thomas Klemm's suggestion above is a much better option. Regards, Gerson. 

08222015, 07:35 PM
Post: #8




RE: root of a quadratic equation
(08222015 09:41 AM)tigger Wrote: Is there a sign for SQRT on this page?
Quote:When I punched the keys in the calculator itself made a blank between the  and the 2. How could I know that the calculator made this mistake? To enter 2 you have to punch the [2] and then the [±] key. Cheers Thomas 

08222015, 08:07 PM
Post: #9




RE: root of a quadratic equation
(08222015 09:41 AM)tigger Wrote: These two equations help to solve a root of a quadratic equation: * and  at the end should be  and +, respectively: << 3 PICK / SWAP ROT 2 * / DUP SQ ROT  SQRT DUP2  ROT ROT + >> On the HP 50g, we can use << PICK3 / SWAP ROT 2 * / DUP SQ ROT  SQRT DUP2  UNROT + >> and save a few bytes. This is 50byte long, 5 bytes shorter than my attempt at this above. Gerson. 

08222015, 08:18 PM
Post: #10




RE: root of a quadratic equation
(08222015 09:41 AM)tigger Wrote: There might be any hope and help to rectify these short programs? Here's a variant from a previous thread using local variables: Code: « → a b c Cheers Thomas 

08222015, 11:06 PM
Post: #11




RE: root of a quadratic equation
(08222015 07:28 PM)Gerson W. Barbosa Wrote: Well, for this example PROOT will give ugly approximations: The simple way to obtain result: 'x²+(√2√3)*x+√6=0' SOLVEVX SIMPLIFY =>> {x=√2 x=√3} 

08232015, 12:43 AM
Post: #12




RE: root of a quadratic equation
(08222015 11:06 PM)Hlib Wrote:(08222015 07:28 PM)Gerson W. Barbosa Wrote: Well, for this example PROOT will give ugly approximations: Well, live and learn! 

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