a) \(2A=2^{101}-2^{100}+2^{99}-2^{98}+...+2^3-2^2\)
\(\Rightarrow3A=A+2A=2^{101}-2\)
\(\Rightarrow A=\frac{2^{101}-2}{3}\)
b) \(3B=3^{101}-3^{100}+3^{99}-3^{98}+...+3^3-3^2+3\)
\(\Rightarrow4B=B+3B=3^{101}+1\)
\(\Rightarrow B=\frac{3^{101}+1}{4}\)
1+2-3-4+...+99+98-99-100
-1+3-5+7...+97-99
tính tổng:
1: 1+(-2)+3+(-4)+........+19+(-20)
2: 1- 2 +3 -4+......+99 - 100
3: 2 - 4+6 - 8+.....+48 - 50
4: -1 + 3 - 5 +7 -.....+97 - 99
5: 1 + 2 - 3 - 4 +.....+97 + 98 - 99 - 100
giải cụ thể hộ mk cái ak ^^
Cho A=\(\dfrac{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{99}+\dfrac{1}{100}}{\dfrac{99}{1}+\dfrac{98}{2}+\dfrac{97}{3}+...+\dfrac{2}{98}+\dfrac{1}{99}}\)
Tính A
D=150-(100-99+98-97+...-3+2-1)
Rút gọn
A= 2^100+2^99+2^98.....+2+1
B=3^100+3^99+3^98....+3+1
C=4^100+4^99+....+4+1
D=2^100- 2^99+....+2^2 - 2 + 1
E=3^100 - 3^99 + 3^98....- 3 +1
Thu gọn
M= 2 + 2^2 + 2^3 ....+ 2^100
Cho A =2+2^2+2^3+....2^100. Tìm số tự nhiên x sao cho A + 1 = 2x
Tính D biết : \(D=\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}{\frac{99}{1}+\frac{98}{2}+\frac{97}{3}+...+\frac{1}{99}}\)
Tính giá trị biểu thức:
101+100+........+3+2+1/101-100+99-98+............+3-2+1
giup tui
1-2+3-4+5-6+,,,+97+98+99-100
1-2-3+4+5-6-7+8.....+97-98-99+100
