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索尼x99和x9
1/1x3x5+1/3x5x7+1/5x7x9+…+1/95
x9
7
x99
简便算法怎么算
答:
1/1x3x5+1/3x5x7+1/5x7x9+…+1/95
x9
7
x99
=1/4(1/(1*3)-1/(3*5)+1/(3*5)-1/(5*7)+.+1/(95*97)-1/(97*99)= (1/4) ( 1/(1x3) - 1/(97x99)= (1/4) (1/3 - 1/9603]=800/9603
1/1x3x5+1/3x5x7+1/5x7x9+…+1/95
x9
7
x99
简便算法怎么算
答:
1/1x3x5+1/3x5x7+1/5x7x9+…+1/95
x9
7
x99
=1/4(1/(1*3)-1/(3*5)+1/(3*5)-1/(5*7)+.+1/(95*97)-1/(97*99)= (1/4) ( 1/(1x3) - 1/(97x99)= (1/4) (1/3 - 1/9603]=800/9603
1x3x7x9……
x99
x101x102的积为啥是偶数
答:
偶数 解析:1×3×7×9×...×
99
×101是奇数 奇数×102=偶数
1/3X5+1/5X7 +1/7X9…+1/97
X99
答:
=1/2(1/3-1/5+1/5-1/7+...+1/97-1/
99
)=1/2(1/3-1/99)=1/2*(32/99)=16/99
100
x99
+98
x9
7+96x95+94x93...+4x3+2x1 求过程!求解!!!
答:
答:100
x99
+98
x9
7+96x95+94x93...+4x3+2x1 =100×100-100+98×98-98+96×96-96+...+2×2-2 =(100²+98²+96²+...+2²)-(100+98+96+...+2)=4×(50²+49²+48²+...+1²)-2×(50+49+48+...+1)=4×50×(50+1)...
1/1x3x5+1/3x5x7+1/5x7x9+…+1/95
x9
7
x99
简便算法怎么算
答:
1/1x3x5+1/3x5x7+1/5x7x9+…+1/95
x9
7
x99
=1/4(1/(1*3)-1/(3*5)+1/(3*5)-1/(5*7)+...+1/(95*97)-1/(97*99)= (1/4) ( 1/(1x3) - 1/(97x99)= (1/4) (1/3 - 1/9603]=800/9603
99
x99
9
x99
9x9999的简便运算
答:
99
x99
9
x99
9x9999 =(99
x99
99)×(999x999)=989901x998001 =987922187901
计算100
x99
-98
x9
7+96x95-94x93...+4x3-2x1=? 求过程,急!
答:
原式=100*(100-1)-98*(98-1)+96*(96-1)-94*(94-1)。。。+4*(4-1)-2(2-1)=100²-100-98²+98+96²-96-94²+94.。。。+4²-4-2²+2 =100²-98²+96²-94²。。。+4²-2²-100+98-96+94...
用简便方法计算6x999十6
x99
x8十8十5
x9
十5
答:
解:6x999+6
x99
x8+8+5
x9
+5 =6x900+6x99+48x99+8+5x(9+1)=6x900+99x(6+48)+8+5x10 =5400+99x54+8+50 =100x54+99x54+58 =54x(100+99)+58 =54x199+58 =54x(200-1)+58 =54x200-54x1+58 =10800+(58-54)=10800+4 =10804 ...
0.75
x99
十 0.75x9十0.75
x99
9简便法
答:
解:原式 =0.75x(
99
+9+999)=0.75x(100-1+10-1+1000-1)=0.75x(1000+100+10-3)=750+75+7.5-2.25 =830.25
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<涓婁竴椤
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