Consider the sequence an=3⋅(x2)n−1a_n = 3 \cdot (\frac{x}{2})^{n-1}an=3⋅(2x)n−1. For what range of xxx does the infinite sum exist?
∣x∣<1|x| < 1∣x∣<1
∣x∣<2|x| < 2∣x∣<2
∣x∣<4|x| < 4∣x∣<4
x>0x > 0x>0