I am trying to follow through a worked example where real roots are expected, but I end up with imaginary roots. Where am I going wrong ? This is solving by a succession of formula substitutions rather than using the factor theorem.
so a2=-2, a1=-5 and ao=6
This results in equation of form x3
p= -19/3 and q = - 56/27.
Now substitute x = w - p/3w to get equation of form w3
) - q = 0.
Multiply through by w3
to get (w3
- q (w3
) - (1/27)p3
I then get (w3
+ (6859/729) = 0
This gives imaginary roots when applying the quadratic formula.
I have been through my workins a number of times but cannot find the error ! Help.