tim 2 so biet
(x+1/2)+(x+1/4)+(x+1/8)+(1/16)
tim x biet : ( x + 1/2 ) + ( x + 1/4 ) + ( x + 1/8 ) + ( x + 1/16 ) = 1
tim x biet
(x+1/2)+(x+1/4)+(x+1/8)+(x+1/16)=1
tim x biet:
(x+1/2)+(x+1/4)+(x+1/8)+(x+1/16)=1
Tim so nguyen x biet : -x/2+2x/3+x+1/4+2x+1/6=3/8
12x/6 + 4x/6 - 3x/6 = 3/8 - 1/4 - 1/6
13x/6 = (9 - 6 - 4)/24 = -1/24
--> x = -1/52
Tim x,y biet:
a. 1/x - y/8 = 1/16
b. |x+1|+|x+2|+|x+3|= x
1. tim A biet :
A = 1/2 x 1/4 x 1/8 x 1/16 x 1/32 x 1/64 x 1/128 x 1/256 x 1/512 x 1/1024
2. tim chu vi cua 1 hinh vuong biet neu giam canh cua hinh vuong do 5 cm thi dien tich giam di 385 cm2
3. co ba nhieu so co 3 chu so ma moi so deu co mot chu so 0
4. tong so tuoi cua 2 anh em hien nay la 30 tim tuoi em hien nay biet khi tuoi anh bang tuoi em hien nay thi tuoi anh gap tuoi em 2 lan
5. 1 day nha co 40 nha so nha cua 40 nha do danhla cac so lien tiep tang dan tong cac so do la 3560. so nha cua nha cuoi cung la bao nhieu
6. cho hinh tam giac ABC tren canh AB lay diem M, N sao cho AM = 1/3 AB. AN bang 1/4 AC dien tich BMNC la 24 cm2 tinh dien tich ABC
câu 1 dễ:
1/2+1/4+1/8+1/16+...+1/1024
=1-1/2+1/2-1/4+1/4-1/16+...+1/512-1/1024
=1-1/1024
=1023/1024
de ko hoc cong thuc nen moi hoi
neu tui noi dung k nhe
tim so nguyen x biet:
1/2-(1/3+3/4)< x < 1/24-(1/8-1/3)
\(\frac{1}{2}-\left(\frac{1}{3}+\frac{3}{4}\right)\le x\le\frac{1}{24}-\left(\frac{1}{8}-\frac{1}{3}\right)\)
\(\Rightarrow\frac{1}{2}-\frac{1}{3}-\frac{3}{4}\le x\le\frac{1}{24}-\frac{1}{8}-\frac{1}{3}\)
\(\Rightarrow\frac{6-4-3}{12}\le x\le\frac{1-3-8}{24}\)
\(\Rightarrow\frac{-1}{12}\le x\le\frac{-10}{24}\)
\(\Rightarrow\frac{-2}{24}\le x\le\frac{-10}{24}\)
\(\Rightarrow-2\le x\le-10\)
\(\Rightarrow x\in\left\{-3;-4;-5;......;-10\right\}\)
tim x biet x la phan so
(x+\(\frac{1}{2}\))+(x+\(\frac{1}{4}\))+(x+\(\frac{1}{8}\))+(x+\(\frac{1}{16}\))=1
Tim so tu nhien x biet:
a,x+(x+1)+(x+2)+...+(x+2010)=2029099
b,2+4+6+8+...+2x=210
a)
\(x+\left(x+1\right)+\left(x+2\right)+...+\left(x+2010\right)=2029099\\ 2011.x+\left(1+2+3+...+2010\right)=2029099\\ 2011.x+2021055=2029099\\ 2011.x=2029099-2021055\\ 2011.x=8044\\ x=8044:2011\\ x=4\)
b)
\(2+4+6+...+2x=210\\ 2.\left(1+2+3+...+x\right)=210\\ 1+2+3+...+x=210:2\\ 1+2+3+...+x=105\\ \dfrac{x.\left(x+1\right)}{2}=105\\ x.\left(x+1\right)=105.2\\ x\left(x+1\right)=210\\ x.\left(x+1\right)=14.15\\\Rightarrow x=14\)
a) x+(x+1)+(x+2)+...+(x+2010)=2029099
x+x+1+x+2+...+x+2010=2029099
2011x+[(2010+1).2010:2]=2029099
2011x+2021055=2029099
2011x=2029099-2021055
2011x=8044
x=8044:2011
x=4
Vậy x=4.
b) 2+4+6+8+...+2x=210
(2x+2)*14:2=210
(2x+2)*7=210
2x+2=210:7
2x+2=30
2x=30-2
2x=28
x=28:2
x=14
Vậy x=14.