Explanation:
3 + 15 + 75 + 375 + 1,875
This is a geometric series. The first term is 3, the common ratio is 5, and the number of terms is 5.
∑₁⁵ 3 (5)ⁿ⁻¹
∑₀⁴ 3 (5)ⁿ
3 + 12 + 48 + 192 + 768
This is a geometric series. The first term is 3, the common ratio is 4, and the number of terms is 5.
∑₁⁵ 3 (4)ⁿ⁻¹
∑₀⁴ 3 (4)ⁿ
4 + 32 + 256 + 2048 + 16,384
This is a geometric series. The first term is 4, the common ratio is 8, and the number of terms is 5.
∑₁⁵ 4 (8)ⁿ⁻¹
∑₀⁴ 4 (8)ⁿ
2 + 6 + 18 + 54 + 162
This is a geometric series. The first term is 2, the common ratio is 3, and the number of terms is 5.
∑₁⁵ 2 (3)ⁿ⁻¹
∑₀⁴ 2 (3)ⁿ