Chứng minh rắng S =1/2+1/2^2+1/2^3+...+1/2^20<1
Chứng minh rắng S= \(\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{20}}< 1\)
\(S=\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{20}}\\ 2S=1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{19}}\\ 2S-S=\left(1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{19}}\right)-\left(\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{20}}\right)\\ S=1-\dfrac{1}{2^{20}}\\ =>S< 1\\ \)
vậy S bé hơn 1
Chứng minh rắng S=1/2+1/22+1/23+.....+1/220<1
S=1/2+1/2^2+1/2^3+...+1/2^20
2S=1+1/2+1/2^2+....+1/2^19
=>2S-S=(1+1/2+1/2^2+...+1/2^19)-(1/2+1/2^2+1/2^3+...+1/2^20)
S=1-1/2^20<1
=>S<1
Vậy S<1
Chứng minh rắng: 100 - ( 1 + 1/2 + 1/3 +.....+1/100) = 1/2 + 2/3 + 3/4 +...+99/100.
100-(1+1/2+1/3+1/4+...+1/100)= (1+1+1+..+1)+(1+1/2+1/3+1/4+...+1/100) = (1-1)+(1-1/2)+(1-/3)+...+(1-1/100)
= 1/2+2/3+3/4+...+99/100 (đpcm)
Chứng minh rằng:
S=1/2+1/2^2+1/2^3+...+1/2^20<1
S = 1/2 + 1/2² + 1/2³ + ... + 1/2²⁰
⇒2S = 1 + 1/2 + 1/2² + ... + 1/2¹⁹
⇒S = 2S - S
= (1 + 1/2 + 1/2² + ... + 1/2¹⁹) - (1/2 + 1/2² + 1/2³ + ... + 1/2²⁰)
= 1 - 1/2²⁰ < 1
Vậy S < 1
chứng minh rằng S = 1/2 + 1/2^2 + 1/2^3+...+1/2^20 <1
S = \(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+.....+\frac{1}{2^{20}}\)
2S = \(1+\frac{1}{2}+\frac{1}{2^2}+.....+\frac{1}{2^{19}}\)
=> 2S - S = \(1-\frac{1}{2^{19}}\)
=> S = \(1-\frac{1}{2^{19}}
Chứng minh:
\(S=\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+....+\dfrac{1}{2^{20}}< 1\)
chứng minh rằng : S=1/2+1/22 +1/ 23 +...1/220 <1
nen 2S=1+1/2+1/2 mu 2 +....1/2 mu 19
do do 2S-S=1-1/2 mu 20 .vay S=1-1/2 mu 20 <1
chứng minh rằng: S= 1/2+1/2^2+1/2^3+...+1/2^20
Giúp mik vs nha
chứng minh răng S = 1/2+1/2^2+1/2^3+.........+1/2^20<1
help vs nhanh lên nha mn!
\(2S=1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{19}}\)
\(2S-S=1-\frac{1}{2^{20}}\)
\(S=1-\frac{1}{2^{20}}< 1\)-> ĐPCM.