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Quartic2.xls

Hello Doug,

Having gone through your excellent and impressive spreadsheet, I find I must do what is nearly the unthinkable. Please tell me how to get started, an example would be fine.

Respectfully,
Claiborne

Claiborne - The quartic (and other) functions work just like a built in Excel function.

If you have a quartic equation: ax^4 + bx^3 + cx^2 + dx +e = 0, then enter the values for the coefficients a to e in five separate cells, say A1 to A5, then the four solutions to the equation are given by:

=quartic(A1, A2, A3, A4, A5, 1) through to:
=quartic(A1, A2, A3, A4, A5, 4)
and the number of real roots is given by
=quartic(A1, A2, A3, A4, A5, 5)

You can also enter
=quartic(A1, A2, A3, A4, A5) in one cell, then select that cell and the three below, and press ctrl-shift-enter, and this will return all four roots of the equation.

Hope that helps

Doug