1.2+2.4+3.5+...+98+100
= 1.( 2 + 1 ) + 2 . ( 3 + 1 ) + 3.( 4 + 1 ) + ... + 98 ( 99 + 1 )
= 1.2 + 1 + 2.3 + 2 + 3.4 + 3 +...+ 98.99 + 98
= ( 1.2 + 2.3 + 3.4 +...98.99 ) +(1+ 2 + 3 +...+ 98 )
= 323400 + 4851 = 328251.
Tick cho mik nha bn nhớ đó!!
Tính tổng sau:
1.3+2.4+3.5+4.6+.....+97.99+98.100
1/1.3 - 1/2.4 + 1/3.5 - 1/4.6+.....+1/97.99-1/98.100
Tính nhanh:
\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{97.99}\)
Tính nhanh các tổng sau G=1.3+2.4+3.5+...+99.101
S =1/1.3-1/2.4+1/3.5-1/4.6+1/5.7 - 1/6.8+1/7.9-1/8.10
Tính nhanh:
S = \(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+.....+\frac{1}{95.97}+\frac{1}{97.99}\)
\(\dfrac{2}{1.3}.\dfrac{3}{2.4}.\dfrac{4}{3.5}...\dfrac{25}{24.26}.\dfrac{26}{25.72}\)
A= 1.3+2.4+3.5+4.6+...........+27.29+28.30
B= 20.22+21.23+...........+32.34+33.35
. là nhân nha các bn
rút gọn biểu thức :
P=(1+ 1/1.3)(1+ 1/2.4)(1+ 1/3.5)......(1+1/49.51)+2/51
