+105 1. What is the explicit rule for the geometric sequence? 120, 40, 40/3, 40/9, 40/27, ...
2. What is the recursive rule for the geometric sequence? 10, −80, 640, −5120, ...
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Thank you to anyone who helps!
The first one is:
Multiply each term by 1/3, so you have:
120, [120x1/3] =40, [40x1/3]=40/3, [40/3x1/3]=40/9...........and so on.
The second one is:
Multiply each term by -8, so you have:
10, [-8x10]=-80, [-80x-8]=640, [640x-8] =-5120........and so on.
+37146 The EXPLICIT formula for the first one:
r = 1/3 a1 = 120
an = a1 * 1/3^(n-1)
The RECURSIVE formula for the second one is
r = -8
an = a(n-1) * (-8)
