a1+a2+a3=3a2=15
a2=5
a1+a3=10 a1*a3=16
由此可得a1=2,a3=8(因为公差为正数,故a1
设{an}是公差为正数的等差数列,若a1+a2+a3=15,a1a2a3=80则a11+a12+a13= 简便方法
设{an}是公差为正数的等差数列,若a1+a2+a3=15,a1a2a3=80则a11+a12+a13= 简便方法
怎么算出a1+a2+a3+(11-1)3d
在得出d=3后怎么得到a1+a2+a3+(11-1)3d这一步
怎么算出a1+a2+a3+(11-1)3d
在得出d=3后怎么得到a1+a2+a3+(11-1)3d这一步
数学人气:786 ℃时间:2020-02-03 00:32:35
优质解答
我来回答
类似推荐
猜你喜欢
- 1I ( )stay in the classroom because I have a bda headache.
- 2If you think you are lonely,you might always be alone啥意思
- 3甲数的7分之5与乙数的5分之4相等,甲:乙=():()
- 4抽屉原理的问题.
- 5已知2+3分之2=2²,3+8分之3=3²乘以8分之3,4+15分之4=4²乘以15分之4
- 6People usually think it too much to answer .
- 7I have had a letter from tom 提问
- 8机械能守恒实例
- 9作文《我和书的故事》
- 10已知m,x,y满足条件:(1)2/3(x-5)^2+5*(m的绝对值);(2)-2a^2b^(y+1)与7b^3a^2是同类项,求代数式