(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8=?

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/15 18:20:33
(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8=?
xSMN@K )`Kh=q0nlMJԸicnEcQ0a׫0Ю mpԭ0!_SŮqb7zȒEwO]J(l/ {ٌ4.A {dq`K,CVd6{,j5^[

(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8=?
(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8=?

(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8=?
一共 (49-1)÷3+1=48÷3+1=17项
(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8
=49x18+46x1/8+...1x1/8-1/8x1/8x17
=1/8x(49+1)x17÷2-17/64
=850/16-17/64
=3400/64-17/64
=3383/64

解题目中的括号有17个
且括弧中的49,46,.......4,1是等差数列
即(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+........+(1-1/8)x1/8
=[(49-1/8)+(46-1/8)+(43-1/8)+........+(1-1/8)]x1/8
=[(49+46+43+....4+1)-17*1/8]x1/8<...

全部展开

解题目中的括号有17个
且括弧中的49,46,.......4,1是等差数列
即(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+........+(1-1/8)x1/8
=[(49-1/8)+(46-1/8)+(43-1/8)+........+(1-1/8)]x1/8
=[(49+46+43+....4+1)-17*1/8]x1/8
=[(49+1)*17/2-17*1/8]x1/8
=17[(49+1)*/2-*1/8]x1/8
=17[25-*1/8]x1/8
=17*25*1/8-17*1/8*1/8
=425/8-17/64
=3383/64

收起