Find the 10th term in the geometric sequence below. 2, –4, 8, –16, … a. –1,024 b. 512 c. 1,024 d. 2,048

This is a geometric progression. Because  -4/2 = 8/-4 = -2. Hence common ratio r = -2 The first term a = 2. Tn for GP  =  ar^(n-1) 10th term,  =  2*(-2)^(10 -1) =  2*(-2)^9 =2*(-512) = -1024 Tenth term = -1024.  Option a.