Write the first five terms of the geometric sequence a1 4 r

Write the first five terms of the geometric sequence. a_1 = 4; r = -2 4, 8, 16, -32, 64 -2, -8, 16, -32, 64 4, -8, 16, -32, 64 4, 2, 0, -2, -4 Use the formula for the general term (the nth term) of a geometric sequence to find the indicated term of the sequence with the given first term, a_1, and common ratio, r. Find a_10 when a_1 = -6, r = -3. -33 118,102 0118,098 -354,294 Use the formula for the sum of the first n terms of a geometric sequence to solve. Find the sum of the first 11 terms of the geometric sequence: 1/8, -3/8, 9/8, -27/8, 81/8, .... 44281/8 22147/4 44287/8 44285/8

Solution

10) a1 = 4; r = -2

G.P. : first five terms a1 , a1r ,a1r^2 , a1r^3 ,a1r^4 = 4 , -8 , 16 , 32, 64

11) a1 = -6 ; r =-3

n the term : an = a1r^(n-1)

tenth term = (-6)*(-3)^(10-1) = (-6)*(-3)^9 =118098

Option C