(1-1/3^5)/(1-1/3)=(3/2)*[(3^5-1)/3^5]
C.E
x²-x-2≥0 x∈(-∞;-1]∪[2;∞)
ridicam la patrat
x²-x-2=2
x²-x-4=0
x1 ,2= (1+-√17)/2 ∈D
AB= √[(3+2)²+3²]=√34
4 (.n+1) * (n+2)=56
n+1=7 n=6 alta solutie naturala nu este pt ca n²+3n+2 crescatoare pt n>0
5. 3*2=6≥20 Fals
4*3=12≥20 fals
5*4=20≥20 adevarat
6*5=30≥20 adevarat
P =nr cazuri favorabile/nr cazuri posibile=2/4=1/2=50%
5. sin (180°-x0=-sinx=-4/5
restu in atach mai putin Ii 1.c) prea mult calcul
