0.999×0.1+0.111×2.7
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0.999*1.3-0.111*1.7=0.111*11.7-0.111-1.7=0.111*10=1.11
=0.111X9X0.7+0.111X3.7=0.111X(6.3+3.7)=0.111X10=1.11
因为1/9用0.111(循环)表示的并不是精确值1=0.999(循环)也并不算错
=(2.992+2.992×10+2.992×100)÷0.111=2.992×(1+10+100)÷0.111=2.992×111÷0.111=2.992×1000=2992
(1.992+19.92+199.2)/0.111=(1.992+1.992*10+1.992*100)/0.111=1.992*(1+10+100)/0.111=1.992*111/0.111=19
简便计算:0.999×1.3-0.111×1.7=0.111×9×1.3-0.111×1.7=0.111×11.7-0.111×1.7=0.111×(11.7-1.7)=0.111×10=1.11诚心
0.999*1.3-0.111*2.7+0.001=0.111*(9*1.3-2.7)+0.001=0.111*(11.7-2.7)+0.001=0.999+0.001=1
[(10的N次方)-1]除以九,得数再除以(10的N次方)
0.999*1.3-0.111*2.7=0.999*1.3-0.111*9*0.3=0.999*1.3-0.999*0.3=0.999*(1.3-0.3)=0.999*1=0.999
0.999×0.6+0.111×3.6=0.999x0.6+0.999x0.4=0.999x﹙0.6+0.4﹚=0.999x1=0.999注3.6=9x0.4,0.111x3.6=0.111x9x0.
0.999*1.3-0.111*1.7=0.111x9x1.3-0.111x1.7=0.111x(11.7-1.7)=0.111x10=1.11请好评~在右上角点击【评价】,然后就可以选择【满意,问题
0.999×0.6+0.111×3.6=0.111×5.4+0.111×3.6=0.111×(5.4+3.6)=0.111×10=1.11
5.9+8.99+12.999+0.111=5.9+8.99+12.999+0.1+0.01+0.001=5.9+0.1+8.99+0.01+12.999+0.001=(5.9+0.1)+(8.99+
9.99*0.13-0.111*2.7=9.99x0.13-0.111x9x0.3=9.99x0.13-0.999x0.3=9.99x0.13-9.99x0.03=9.99x(0.13-0.03)=9
0.111*5.5+0.555*0.9=0.111×5.5+0.111×4.5=0.111×(5.5+4.5)=0.111×10=1.11
是,数列中的项总小于1/9
这是极限思想再答:每个有理数都可以取极限再问:意思是1=0.999......再答:呵呵这就是极限思想
原式=9*0.111*1.3-0.111*2.7=(9*0.3+9*1)*0.111-0.111*2.7=2.7*0.111+0.999-0.111*0.27=0.999
第一个:1-(0.1)^n即1减去0.1的n次方第二个:[1+(-1)^(1+n)]/2即负1的1+n次方与1的和再除以2第三个:(n+2)/(3n+2)第四个:(-1)^n*{[n(n+2)]/(2