Hi , I don't know what's going on here with the sigma notation (attached question and answer) .

A simplified explanation would be greatly appreciated .

Thank you

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- Nov 25th 2012, 12:15 PMminicooper58Roots of Cubic
Hi , I don't know what's going on here with the sigma notation (attached question and answer) .

A simplified explanation would be greatly appreciated .

Thank you - Nov 25th 2012, 12:22 PMcoolgeRe: Roots of Cubic
There are a many sigmas/ Which one are you referring to?

- Nov 25th 2012, 12:25 PMminicooper58Re: Roots of Cubic
Hi , alpha=2 the first one and then why gamma is omitted in the second .

- Nov 25th 2012, 12:37 PMPlatoRe: Roots of Cubic

The cubic is $\displaystyle z^3-2z^2+0z+k=0$

The sum of the roots; $\displaystyle \alpha+\beta+\gamma=2$

The product of roots two at a time: $\displaystyle \alpha\beta+\alpha\gamma+\beta\gamma=0$

The products of the roots: $\displaystyle \alpha\beta\gamma=-k$