(35S ALG) Quadratic Equation Solver (with complex solutions support) - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: General Software Library (/forum-13.html) +--- Thread: (35S ALG) Quadratic Equation Solver (with complex solutions support) (/thread-3401.html) (35S ALG) Quadratic Equation Solver (with complex solutions support) - BartDB - 03-17-2015 10:57 AM Based on this article: http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=1003 It is a simple program using the traditional quadratic root formula: $$\frac{-b±\sqrt{b^{2}-4ac}}{2a}$$ the program is converted for use in ALG mode: Code:  Q001 LBL Q Q002 CF 10 Q003 INPUT A Q004 INPUT B Q005 INPUT C Q006 -B÷(2×A)       ;the first - is the +/- key Q007 LASTx STO R    ;LASTx is blue ENTER, a black > will show instead of STO Q008 B^2-4×A×C      ;using y^x instead of x^2 Q009 x>=0? Q010 GTO Q015 Q011 -LASTx         ;press +/- key followed by LASTx Q012 SQRT(LASTx) Q013 i×LASTx Q014 GTO Q016 Q015 SQRT(LASTx) Q016 LASTx÷(2×A) Q017 R+LASTx Q018 R-REGY         ;for REGY press Roll Down (E-key) & if necessary underline Y Q019 RTN Press x<>y to see the other root. In RPN mode the 35s will dispay 2 lines, thus both roots. In ALG mode only one line is displayed. After running the program, use x<>y to swap between roots.