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help for solvcui, solvqui                             (Author:  David Harrison)
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Find real roots of cubic and quadratic polynomials

    solvcui a b c d

    solvcui e f g

    solvqui a b c


Description

    solvcui finds the real roots of a cubic polynomial of the form

        ax³ + bx² + cx + d = 0 (first syntax)

    or

        x³ + ex² + fx + g = 0 (second syntax)

    solvqui finds the real roots of a quadratic polynomial of the form

        ax² + bx + c = 0

    Both commands use formulae designed to minimize roundoff error. No output
    is displayed to the screen, but the roots are returned as scalars in
    ascending order in r(x1), r(x2) and (for solvcui) r(x3); see help return.
    Complex roots return missing. The commands are immediate, all their
    arguments are numbers; see help immed.


Examples

    . solvcui 2 -7 7 -2

    . solvcui -6 11 -6

    . solvqui 1 -9 20


Maintainer

    David A. Harrison
    Intensive Care National Audit & Research Centre
    david@icnarc.org


Also see

    Online:  help for return, immed