S= 2^1+2^2+2^3+....+2^15+2^16?
S=
2^1+2^2+2^3+....+2^15_2^16?
Giải:
S=21+22+23+…….+215+216.
=>2S=2.( 21+22+23+…….+215+216)
=22+23+24+……..+216+217.
=>2S-S=(22+23+24+……..+216+217)-
( 21+22+23+…….+215+216)
=>S=217-21=131072-2=131070
Trang Trước
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