Question

Cu cine e egal x1^4 +x2^4??

Answer 1

Daca e vorba de ecuatia de gradul II:ax^2+bx+c=0, avem egalitatea $x_{1}^4+ x_{2}^4=( x_{1}^2+ x_{2}^2)^2-2 x_{1}^2 x_{2}^2 =(S^2-2P)^2 -2P^2 .$ , unde S=-b/a si P=c/a.