天山 04-06

[schung0529]

In the sequence 1,2, 4, 16,32..., each term after the first is twice the previous term. What is the sum of the 16th, 17th,18th terms in the sequence?
A. 2^18
B. 3(2^17)
C. 7(2^16)
D. 3(2^16)
E. 7(2^15)

2^15+ 2^16+2^17...然後我就不知道了

[waleaaa]

　 2^15 + 2^16 + 2^17
＝ 2^15 (1 + 2^1 + 2^2)
＝ 2^15 X 7
所以選E

[schung0529]

　 2^15 + 2^16 + 2^17
＝ 2^15 (1 + 2^1 + 2^2)
＝ 2^15 X 7
所以選E

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