Các câu hỏi tương tự
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!
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=\(1-2^2+3^2-4^2+5^2-6^2+...+99^2-100^2\)
d) G= 1.1!+ 2. 2!+3.3!+ ... +100.100!
CMR; A chia het cho 10 , biet ;
A = 9+99+999+.....+9999...99( so cuoi cung co 50 chu so 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)
thu gon tong sau
9 +99+999+9999+...+999...9/100 chu so 9
rút gọn phân số: 1999...999/99..995( 10 chu so 9 o tu,10 chu so 9 o mau)
9+999+99999+...+99...9[15 so 9]
Tính giá trị:
T = 9 + 99 + 999 + 9999 + .... + 999...9 (có 2020 số 9) + 999...99 (có 2021 số 9)