Attempt following question by selecting a choice to answer.
D
Find the common ratio of the geometric sequence for which
a5 = 324 and
a7 = 2916.
cc DDA.
D± 4
B.
D± 5
C.
D± 1
D.
D± 3
D
D
Step 1: an = a1 rn - 1[Use the formula for the nth term.]
Step 2: 324 = a1 × r5 - 1[Replace n = 5 and a5 = 324.]
Step 3: 324 = a1 × r4→ Equation 1
Step 4: 2916 = a1 × r7 - 1[Replace n = 7 and a7 = 2916.]
Step 5: 2916 = a1 × r6→ Equation 2
Step 6: 2916324 = a1r6a1r4
[Divide equation 2 with 1.]
Step 7: 9 = r2[Simplify.]
Step 8: ± 3 = r[Solve for r.]
Step 9: So, the common ratio is ± 3.