几道数学计算题简算!要答案和过程!
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/09/02 00:28:20
几道数学计算题简算!要答案和过程!
1、(1+1/3+1/5+1/7)×(1/3+1/5+1/7+1/9)-(1+1/3+1/5+1/7+1/9)×(1/3+1/5+1/7)
2、(1+1/2+1/3+1/4+1/5)×(1/3+1/4+1)-(1+1/3+1/4)×(1/2+1/3+1/4+1/5)
3、(1+1/5-0.1+2/15)×(0.2-1/10+2/15+19/6)-(1+1/5-1/10=2/15=19/6)×(0.2-0.1+2/15)
第3题改为:
3、(1+1/5-0.1+2/15)×(0.2-1/10+2/15+19/6)-(1+1/15-1/10+2/15+19/6)×(0.2-0.1+2/15)
1、(1+1/3+1/5+1/7)×(1/3+1/5+1/7+1/9)-(1+1/3+1/5+1/7+1/9)×(1/3+1/5+1/7)
2、(1+1/2+1/3+1/4+1/5)×(1/3+1/4+1)-(1+1/3+1/4)×(1/2+1/3+1/4+1/5)
3、(1+1/5-0.1+2/15)×(0.2-1/10+2/15+19/6)-(1+1/5-1/10=2/15=19/6)×(0.2-0.1+2/15)
第3题改为:
3、(1+1/5-0.1+2/15)×(0.2-1/10+2/15+19/6)-(1+1/15-1/10+2/15+19/6)×(0.2-0.1+2/15)
1.令a=1/3+1/5+1/7,b=1/3+1/5+1/7+1/9
原式变为(1+a)×b-(1+b)×a
=b+ab-a-ab
=b-a=1/9
2.(1+1/2+1/3+1/4+1/5)×(1/3+1/4+1)-(1+1/3+1/4)×(1/2+1/3+1/4+1/5)
=(1/3+1/4+1)×[(1+1/2+1/3+1/4+1/5)-(1/2+1/3+1/4+1/5)]
=(1/3+1/4+1)×1
=1/3+1/4+1
=19/12
3、(1+1/5-0.1+2/15)×(0.2-1/10+2/15+19/6)-(1+1/5-1/10=2/15=19/6)×(0.2-0.1+2/15)
=(1+1/5-1/10+2/15)×(1/5-1/10+2/15+19/6)-(1+1/5-1/10+2/15+19/6)×(1/5-1/10+2/15)
令a=1/5-1/10+2/15,b=1/5-1/10+2/15+19/6
原式变为(1+a)×b-(1+b)a
=b+ab-a-ab
=b-a=19/6
原式变为(1+a)×b-(1+b)×a
=b+ab-a-ab
=b-a=1/9
2.(1+1/2+1/3+1/4+1/5)×(1/3+1/4+1)-(1+1/3+1/4)×(1/2+1/3+1/4+1/5)
=(1/3+1/4+1)×[(1+1/2+1/3+1/4+1/5)-(1/2+1/3+1/4+1/5)]
=(1/3+1/4+1)×1
=1/3+1/4+1
=19/12
3、(1+1/5-0.1+2/15)×(0.2-1/10+2/15+19/6)-(1+1/5-1/10=2/15=19/6)×(0.2-0.1+2/15)
=(1+1/5-1/10+2/15)×(1/5-1/10+2/15+19/6)-(1+1/5-1/10+2/15+19/6)×(1/5-1/10+2/15)
令a=1/5-1/10+2/15,b=1/5-1/10+2/15+19/6
原式变为(1+a)×b-(1+b)a
=b+ab-a-ab
=b-a=19/6