已知数列{an}满足a1=1,an=a1+2a2+3a3.+(n-1)an-1 (n>=2),则{an}的通项是什么
已知数列{an}满足a1=1,an=a1+2a2+3a3.+(n-1)an-1 (n>=2),则{an}的通项是什么
过程要看得懂的
过程要看得懂的
数学人气:500 ℃时间:2019-09-03 10:43:55
优质解答
an=a1+2*a2+3*a3.+(n-1)*a(n-1)a(n+1)= a1+2*a2+3*a3.+(n-1)*a(n-1)+n*an作差:a(n+1) -an = n*ana(n+1)=(n+1)*an利用累积法:当n=1时,a2=2*a1当n=2时,a3=3*an当n=3时,a4=4*a3--------当n-1时,an=n*a(n-1)相乘:a2*a...
我来回答
类似推荐
- 已知数列{an}满足a1=1,an=a1+2a2+3a3.+(n-1)an-1 (n>=2),则{an}的通项是什么
- 已知数列{an}满足a1=1,an=a1+2a2+3a3+…+(n-1)an-1,则n≥2时,数列{an}的通项an=( ) A.n!2 B.(n+1)!2 C.n! D.(n+1)!
- 已知数列{an}满足a1=1,an=a1+2a2+3a3+…+(n-1)an-1,则n≥2时,数列{an}的通项an=( ) A.n!2 B.(n+1)!2 C.n! D.(n+1)!
- 若数列{an}满足a1+2a2+3a3+…+nan=n(n+1)(n+2)(n∈N*),求{an}的通项公式.
- 数列an满足a1+2a2+3a3+...+nan=(n+1)(n+2) 求通项an
猜你喜欢
- 1将一个棱长为一分米的正方体锯成棱长为一厘米的小正方体,能锯成多少块?
- 2为什么说马克思主义认识论是能动的反映论?
- 3Could you please not smoke in the room?或Would you mind not smoking in the room?的区别
- 4《生活需要爱》600字作文
- 5I was having dinner at a restaurant when Tony Steele came in.
- 6若根号(2a-1)的平方=1-2a,则( )
- 7一个圆形花坛的周长是50.24M,其中5/3面积是草皮,余下的面积是多少?
- 8《青海高原一株柳》第八段比喻句是哪一句?
- 91.The old buildings ,___ the seventeenth century,were destroyed in the earthquake.(C)
- 10如图P是△ABC所在平面外一点,PA=PB,CB⊥平面PAB,M是PC的中点,N是AB上的点,AN=3NB.求证:MN⊥AB.