找规律:2x^2,-3x^3,5x^4,-9x^5,17x^6,-33x^7……第n个数是__第8个数是__

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/01 21:50:08
找规律:2x^2,-3x^3,5x^4,-9x^5,17x^6,-33x^7……第n个数是__第8个数是__

找规律:2x^2,-3x^3,5x^4,-9x^5,17x^6,-33x^7……第n个数是__第8个数是__
找规律:2x^2,-3x^3,5x^4,-9x^5,17x^6,-33x^7……第n个数是__第8个数是__

找规律:2x^2,-3x^3,5x^4,-9x^5,17x^6,-33x^7……第n个数是__第8个数是__
罗辑题,涉及到等差数列,数字之间相差1,-2,4,-8,16,仔细观察你会发现2和3之间相差2的0次方,3和5之间差2的1次方,你明白了吧?第n项为(-1)^n*2^(n-1)*x^(n+1),则第八项为2^(8-1)*x(8+1)=128x^9

(-1)^(n-1)*[2^(n-1)*+1]x^(n+1)
大概是这样子,打电话问问闺蜜??

第n个数是

第8个数是