2/ 2 * 4 + 2/4 * 6 + 2/ 6 * 8 + ....... + 2/ 98 * 100
Những câu hỏi liên quan
100+98+96+94+...+8+6+4+2
_______________________
100-98+96-94+...+8-6+4-2
\(\frac{100+98+96+94+...+4+2}{100-98+96-94+...+4-2}\)
\(=\frac{\text{[}\left(100-2\right):1+1\text{]}.102:2}{2+2+2+...+2\left(51s\text{ố}2\right)}\)
\(=\frac{5049}{102}=49\frac{1}{2}\)
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Tính nhanh 2/2·4+2/4·6+2/6·8+.........+2/96·98+2/98·100
Đặt \(A=\frac{2}{2\cdot4}+\frac{2}{4\cdot6}+\frac{2}{6\cdot8}+...+\frac{2}{96\cdot98}+\frac{2}{98\cdot100}\)
\(A=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{98}-\frac{1}{100}\)
\(A=\frac{1}{2}-\frac{1}{100}\)
\(A=\frac{50}{100}-\frac{1}{100}=\frac{49}{100}\)
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tính 2/2*4 + 2/4* 6 + 2/6*8+.....2/98*100
\frac{2}{2\cdot 4}+\frac{2}{4\cdot 6}+\frac{2}{6\cdot 8}+...+\frac{2}{98\cdot 100}
=1/2-1/4+1/4-1/6+...+1/98-1/100
=1/2-1/100
=49/100
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2*4+4*6+6*8+...+98*100+100*102
tính
B=2*4*6+4*6*8+6*8*10+...+94*96*98+96*98*100
A = 1-2+3-4+5-6+.....+97-98+99-100+101
B = 1+2-3-4+5+6-7-8+......+98-99-100+101
B=1+2-(3+4)+5+6-..-100+101
B=(3+11+19+...+195)-(7+15+...+199)+101
B=25.99-25.103+101
B=-100+101=1
Vậy B=1
a=151
B=1 nha
Xem thêm câu trả lời
D = 1 - 6 + 11 - 16 + ... + 111
F = 2^100 - 2^99 - 2^98 - ...- 2^2 - 2 - 1
E = 1 + 2 - 3 -4 +5 + 6 - 7 - 8 +....+ 249 + 250
H = 1 -2 -3 -4 - 5 -6 - ... -97 - 98 - 99 - 100
Tính nhanh:
a) 4.13.6+12.76.2+11.8.3
b) 2-4+6+8+10-12+...+98-100
c) (2+4+6+...+100) . (36.333-108-111)
d) 1-2-3+4+5-6-7+...+97-98-99+100
a) = 13 x 24 + 24 x 76 + 11 x 24 d)= (1-2-3+4)+(5-6-7+8)+...+(97-98-99+100)
= 24 x ( 13 + 76 + 11 ) = 0 + 0 +...+ 0
= 24 x 100 =0
= 2400
CÓ VIỆC BẬN NÊN MÌNH CHỈ LÀM ĐC ĐẾN ĐÓ THÔI !
d) 1-2-3+4+5-6-7+...+97-98-99+100
=(1-2-3+4)+(5-6-7+8)+(9-10-11+12)+......+(97-98-99+100)
=0+0+0+0+.....+0
=0
Vay bang 0
c) (2+4+6+...+100) . (36.333-108-111)
Ta chia hai tich tren la A va B, ta co:
A=(2+4+6+...+100)
B=(36.333-108-111)
A co ssh la:(100-2):2+1=45(ssh)
B=36.333-108-111
=>
A=(100+2)x45:2=2295
B=36.(111.3)-108-111=111.(36.3)-108-111=111.108-108.1-111=(111.8-108.1)-111=11880-111=11769
=>
A.B =2295.11769=( bam may tinh )27009855