Hi, can anyone help me to prove this:

If the roots of the equation

$\displaystyle x^3-Lx^2+mx+n=0$

are the cosine of the angles of a triangle

show that: $\displaystyle L^2=2m+2n+1$

Printable View

- Jan 15th 2012, 01:32 PMrazemsoft21Roots of equation
Hi, can anyone help me to prove this:

If the roots of the equation

$\displaystyle x^3-Lx^2+mx+n=0$

are the cosine of the angles of a triangle

show that: $\displaystyle L^2=2m+2n+1$ - Jan 15th 2012, 06:01 PMTKHunnyRe: Roots of equation
Well, you have three angles. Use them and see what happens.

$\displaystyle \alpha$, $\displaystyle \beta$, $\displaystyle \pi - \alpha-\beta$

You have a Law of Cosines.

Show us what you get.