Jia is skipping a rock across a pond. The sequence {4.2, 3.57, 3.0345, 2.5793, …} describes the height of the rock on each successive skip. Which explicit formula describes this geometric sequence? an=4.2(0.15)n−1
an=0.85(4.2)n−1
an=4.2(0.85)n−1
an=3.57(4.2)n−1