Practice problem
Which formula describes the periodic sequence a=−2,2,−2,2,−2,2,…,a = -2,2,-2,2,-2,2,\dots,a=−2,2,−2,2,−2,2,…, using n=1n=1n=1 for the first term?
an=(−2)na_n = (-2)^nan=(−2)n
an=−2(−1)na_n = -2 (-1)^nan=−2(−1)n
an=2(−1)na_n = 2 (-1)^nan=2(−1)n
an=2(−1)n−1a_n = 2 (-1)^{n-1}an=2(−1)n−1
Type a concept, like “slope” or “photosynthesis”.
