Answer:
(-1)ⁿ(3)ⁿ/10
Explanation:
The first term a = 0.3, the second term, ar = 0.9. The common ratio r = ar/a = 0.9/-0.3 = -3.
From the general term of a geometric series,
U = arⁿ⁻¹
= (0.3)(-3)ⁿ⁻¹
= (3/10)(-3)ⁿ⁻¹
= (-1)ⁿ⁻¹(3)(3)ⁿ⁻¹/10
= (-1)ⁿ(3)ⁿ/10