Các câu hỏi tương tự
Tính:
S= 9+99+999+9999+......+99....999(40 cs 9)
Tính 9+99+999+(999...9)100C\S 9
Tinh tong: a) 9 + 99 + 999 + ... + 999...999 ( co 10 c/s 9 )
b) Tim x, biet: 1/21 + 1/28 = 1/36 +... + 2/x(x+1) = 2 / 9
Tính
S1=9+99+999+...+99...9(10 c/s 9)
GIUP MK CAU NAY VS
a. Tim chu so a va so tu nhien x sao cho (12 +3x)2 = 1a96
b. Tinh gia tri bieu thuc : S= 9+99+999+9999+....+99..99(2017 so 9)
Tinh tong
a) D= 9+99+999+9999+...+999....9 (50 chu so 9)
b) E= 9+99+999+...+999...9 (200 chu so 9)
c)C=1−2^2+3^2−4^2+...+99^2−100^2
d) G= 1.1!+ 2. 2!+3.3!+ ... +100.100!
Tinh tong
a) D= 9+99+999+9999+...+999....9 (50 chu so 9)
b) E= 9+99+999+...+999...9 (200 chu so 9)
c) C=\(1-2^2+3^2-4^2+...+99^2-100^2\)
d) G= 1.1!+ 2. 2!+3.3!+ ... +100.100!
B=9+99+999+...+999 999 999 999
Tính giá trị:
T = 9 + 99 + 999 + 9999 + .... + 999...9 (có 2020 số 9) + 999...99 (có 2021 số 9)