怎样计算:8/32+16/152+24/352+32/632+40/992+48/1432

显示全部楼层 · 2012-4-5 20:03:57

先学学吧x^y表示X的Y次方这人令S=8/2^5+8*2/2^7+8*3/2^9+8*4/2^11+8*5/2^13+8*6/2^15
不难看出S为差比数列1/4S=0
+ 8/2^7+8*2/2^9+8*3/2^11+8*4/2^13+8*5/2^15+8*6/2^17
1/4S-S=8(1/2^5+1/2^7+1/2^9+1/2^11+1/2^13+1/2^15)+8*6/2^17这好像错的还是我来吧...

千问 · 2012-4-5 20:03:57

令S=8/2^5+8*2/2^7+8*3/2^9+8*4/2^11+8*5/2^13+8*6/2^15
不难看出S为差比数列1/4S=0
+ 8/2^7+8*2/2^9+8*3/2^11+8*4/2^13+8*5/2^15+8*6/2^17
1/4S-S=8(1/2^5+1/2^7+1/2^9+1/2^11+1/...