Formulae for alpha square plus beta square.
Establish the formula:
We know that,
α+β2=α2+β2+2αβ
Subtracting 2αβ on both sides, we get
α+β2-2αβ=α2+β2+2αβ-2αβ
⇒α+β2-2αβ=α2+β2
Therefore, the formula for α2+β2 is α+β2-2αβ.