1/2.5+1/5.8+1/8.11+...+1/152.155
=1/3(3/2.5+3/5.8+3/8.11+...+3/152.155
=1/3(1/2-1/5+1/5-1/8+1/8-1/11+...+1/152-1/155)
=1/3(1/2-1/155)
=1/3(155/310-2/310)
=1/3.153/310=51/310
Kết quả:51/310
A= 1/2.5+1/5.8 + 1/8.11 +........ 1/152.155
A =1/2.5 + 1/5.8 + 1/8.11 + .... 1/152.155 = ?
A= 1/2.5+1/5.8+1/8.11+...+1/92.95+1/95.98.
Tính tổng A
Tính S
S=1/2.5+1/5.8+1/8.11+1/11.14+1/14.17+1/17.20
A= 1/2.5+1/5.8+1/8.11+...+1/92.95+1/95.98.
Tính tổng A?
A= 1/2.5 + 1/5.8 + 1/8.11 + .....+ 1/150.153
b=1/2.5+1/5.8+1/8.11+...+1/92.95
D=1/2.5+1/5.8+1/8.11+...+1/1979.1982
Tính A = 1/2.5 + 1/5.8 + 1/8.11 + ... + 1/92.95 + 1/95.98
Cho lời giải cụ thể với ạ. Em cảm ơn!
