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1/2+1/4+1/8+1/16+1/32+1/64 7/6+37/12+101/20+211/30+379/421/3
题目内容:
1/2+1/4+1/8+1/16+1/32+1/64
7/6+37/12+101/20+211/30+379/42
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45
1/2+1+3/2+2+5/2+...+30
1+11/2+55/6+157/12+341/20+631/30+1051/42
3/2-5/6+7/12-9/20+11/30-13/42优质解答
1/2+1/4+1/8+1/16+1/32+1/64
没简单是算法 通分,=63/64
7/6+37/12+101/20+211/30+379/42
=1+1/6+3+1/12+5+1/20+7+1/30+9+1/42
=1+3+5+7+9+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+.+(1/6-1/7)
=25+1/2-1/7
=25+5/14
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45
=1/2+.
=3/5+...
=2/3+...
=15/21+.
=21/28+.
=28/36+.
=21/45=7/15
1/2+1+3/2+2+5/2+...+30
=(1+2+...+60)/2
=(1+60+2+59+3+58+30).../2
=(29*61+30)/2
=899.5
1+11/2+55/6+157/12+341/20+631/30+1051/42
=1+5+1/2+9+1/6+13+1/12+17+1/20+31+1/30+25+1/42(同第二题)
3/2-5/6+7/12-9/20+11/30-13/42
=3/2-(1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)
=1+1/2-1/2-1/3+1/3+1/4-1/4-1/5+1/5+1/6-1/6-1/7
=1-1/7
=6/7
方法应该基本对,计算可能有失误,请自己仔细演算一下
7/6+37/12+101/20+211/30+379/42
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45
1/2+1+3/2+2+5/2+...+30
1+11/2+55/6+157/12+341/20+631/30+1051/42
3/2-5/6+7/12-9/20+11/30-13/42
优质解答
没简单是算法 通分,=63/64
7/6+37/12+101/20+211/30+379/42
=1+1/6+3+1/12+5+1/20+7+1/30+9+1/42
=1+3+5+7+9+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+.+(1/6-1/7)
=25+1/2-1/7
=25+5/14
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45
=1/2+.
=3/5+...
=2/3+...
=15/21+.
=21/28+.
=28/36+.
=21/45=7/15
1/2+1+3/2+2+5/2+...+30
=(1+2+...+60)/2
=(1+60+2+59+3+58+30).../2
=(29*61+30)/2
=899.5
1+11/2+55/6+157/12+341/20+631/30+1051/42
=1+5+1/2+9+1/6+13+1/12+17+1/20+31+1/30+25+1/42(同第二题)
3/2-5/6+7/12-9/20+11/30-13/42
=3/2-(1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)
=1+1/2-1/2-1/3+1/3+1/4-1/4-1/5+1/5+1/6-1/6-1/7
=1-1/7
=6/7
方法应该基本对,计算可能有失误,请自己仔细演算一下
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