Solving a cubic equation using trigonometry, but with a2 term?  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: Solving a cubic equation using trigonometry, but with a2 term? (/thread198450.html) 
Solving a cubic equation using trigonometry, but with a2 term?  snaggs  09292011 Hi, 00 { 31Byte Prgm } 00 { 34Byte Prgm } However, it doesn't work if you have an a2 term, unless I've made a typo. Having to do substitution before using the program seems to defeat the purpose. Daniel. Re: Solving a cubic equation using trigonometry, but with a2 term?  Dieter  09292011 Sure there is no a2 term: That's why it says "A general cubic equation can be transformed to the following form using a substitution". ;) For more details see below.
There are wellknown standard methods for solving cubic equations. Just take a look at de.wikipedia.org  as well as the last link ("Leitfaden") on that page for a stepbystep solution. The entry on Having read all this you may finally proceed to the actual algorithm. ;) For instance by using Cardano's method as described on de.wikipedia.org. This is the method you will probably use.
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Dieter Edited: 29 Sept 2011, 8:49 a.m.
