A=1.2+2.3+3.4+........+98.99
3A=1.2.3+2.3.3+3.4.3+........+98.99.3
3A=1.2.3+2.3.(4 -1) +3.4.(5 -2)+........+98.99.(100 -97)
3A=1.2.3+2.3.4 -1.2.3
3A=98.99.100
=>A=(98.99.100)/3
=323400
1.2+2.3+3.4+....+98.99+99.100=
1.2+2.3+3.4+4.5+...+98.99+99.100=?
B=1.98+2.97+3.96+......+98.1/1.2+2.3+3.4+....+98.99 = ?
tính tổng sau bằng cách hợp lí: S= 1.2 + 2.3 + 3.4 + 4.5 +...+ 98.99.
a,1.98+2.97+3.96+...+98.2+99.1
1.2+2.3+3.4+...+98.99
A=1.2+2.3+3.4+4.5+...+98.99
B=1^2+2^2+3^2+4^2+...+98^2
tính A-B
Tính
\(\frac{2}{1.2}-\frac{2}{2.3}-\frac{2}{3.4}-...-\frac{2}{98.99}-\frac{2}{99.100}\)
Tính A = 1.2 + 2.3 + 3.4 + … + n.(n + 1)
ai làm được mình tick cho
Tìm x
x - \(\left(\frac{1}{1.2}-\frac{1}{2.3}-\frac{1}{3.4}-...-\frac{1}{98.99}-\frac{1}{99.100}\right)=\frac{1}{100}\)
