1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.
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![1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.](/uploads/image/z/1789159-31-9.jpg?t=1%3A-2%2C4%2C-8%2C13%2C-32...2%3A-4%2C8%2C-16%2C32%2C-64.3%3A-4%2C2%2C-10%2C14%2C-34.%E6%89%BE%E5%87%BA%E5%90%84%E8%A1%8C%E8%A7%84%E5%BE%8B%2C%E8%AE%A1%E7%AE%97%E5%90%84%E7%BB%84%E7%AC%AC8%E4%B8%AA%E6%95%B0%E7%9A%84%E5%92%8C.)
1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.
1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.
1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.
第一组;(-1)^n *2^n 第四个数比较特殊(减去前面个数),所以依次类推第八个数为256-7=249
第二组;(-1)^n *2^(n+1),所以第八个数为512
第三组:(-1)^n *2^n-2,所以第八个数为256-2=254
所以和为1015