Question

25 DE PUNCTE!!!
VA ROG AM DOUA PROBLEME VA ROG AJUTOR DAU COROANA SI 25 DE PUNCTE

Answer 1

[tex](a+b)^2=1\\ a^2+2ab+b^2=1\\ a^2+b^2=1-2ab\\ a^4+b^4+2a^2b^2=1-4ab+4a^2b^2\\ a^4+b^4+1=2-4ab+2a^2b^2=2(1-2ab+a^2b^2)=2(ab-1)^2\\ e_{(a,b)}=\frac{2(ab-1)^2}{(ab-1)^2}=2\\ 2) [/tex]
La ex 3 e o greseala ! [tex]A=\{x\in R|x^3-2x^2-x+2=0}\}\\ x^2(x-2)-(x-2)=(x-2)(x^2-1)=(x-2)(x-1)(x+1)=0\\ x-2=0\\x_1=2\\ x-1=0\\ x_2=1\\ x+1=0\\ x_3=-1\\ A=\{2,1,-1\}\\ [/tex]
A∩{1,2,3}={1,2}, deci raspunsul corect este c) 2

Answer 2

Atasez exercitiul 2)

La 3, cred ca este greseala de scriere in carte.. trebuia sa fie x^3-2x^2-x+2 = 0