Explicație pas cu pas:
2.a=(0,2×5/V3 + V3/6)×2
(1/5×5V3/3+V3/6)×2
(1/5×10V3/6+V3/6)×2
(10V3/30+5V3/30)×2
15V3/30×2 =
30V3/30=
V3
V3 aparține (1;2)
3.a=3²ⁿ+³+2×9ⁿ+¹+12×3²ⁿ-¹ : 7
3²ⁿ×3³ + 2×3×3ⁿ×3×3+3×4×3²ⁿ:3 =
3(1²ⁿ×3² + 2×1ⁿ+2×2×1²ⁿ)=
3ⁿ(1²×3² + 2 + 4×1²)=
3ⁿ(9+1+4)=3ⁿ × 14 : 7
