利用数学归纳法
(1)当n=1时,显然成立.
(2)假设当n=k时,命题成立,即 k^3 +5k被6整除.
当n=k+1时,
(k+1)^3 +5(k+1)=k^3+3K^2+3k+1 +5k+5
=(k^3+5k) + (3k^2 +3k) +6
=(k^3+5k) + 3*k(k+1) +6
(k^3+5k) 被6整除(假设的条件),3*k(k+1)和 6都被6整除.
所以当n=k+1时也成立.
猜你喜欢
- 1three other students = another three students (⊙_⊙)?
- 2作文 《两代人的对话》 写800字,
- 3一根钢管,每锯断一次的时间相等,锯成4段用的时间与锯成8段所用时间的比( )
- 4出色源自专业 翻译成英文哪个更好?Excellent from professionals Excellent Because of Profession
- 5It takes me 25 minutes to go to the nearest shop.(划线提问) --- --- it ---you to go to----------
- 66尺8寸等于多少厘米?
- 7关于Lewis酸碱的分类问题
- 8look,this is my new skirt.How nice!A so B what C too 把how换掉,但意思相同
- 9抒发积极进取的古代诗句
- 10Would you like to( )me some questions about myself?A.tell B.ask C.listen D.take