exe 4 .
2,(1) +2, (3)+2,(5)=2+2+2+0,(1) +0,(3)+0,(5)=6+1/9+3/9+5/9=
=6+9/9=6+1=7∈N
test auto evaluare
1. 18/1a a∈{1,3,7}
2) 40-2=38 38:3=...rest2 deci a 40-a zecimala e a doua din grupul de 3, si anume 2
3. 2x+1∈{6,5,4,3,2,1} 2x∈{5;4;3;2;1;0} x natural x∈{0;1;2}
4. 12/(x+16)=16/(x+28)
3/x+16=4/x+28
(x+16)/3 =(x+28)/4
4x+64=3x+84
x=20
5. 2,35555...>2,353535..
6 . √6 (3√6+6√6)=√6*9√6=6*9∈Z⊂Q, deci propozitia e FALSA
II
1.2,08(3) = (2083-208)/900=1875/900=75/36=25/12 raspuns corect D
2.1,85 corect B (princalcul direct)
3 calcul direct rezulta b
4.practic se cere sa scoatem numerele iratioinale, sa vedem cate rationale raman
rationale sunt numerele;3;1,5; 5/2 ;-7;-8 in toal5 numere; cardinalul cerut este 5; rapuns B
III 288(288-285)-135= 288*3-135=(calculator)=729
√729=27∈N⊂Q deci rational
