\(3A=3^2+3^3+3^4+...+3^{101}\)
\(3A-A=\left(3^2+3^3+...+3^{101}\right)-\left(3+3^2+...+3^{100}\right)\)
\(2A=3^{101}-3\)
\(A=\frac{3^{101}-3}{2}\)
Học tốt~
Tinh tong sau:
N=1^1+2^2+3^3+...+100^100. So sanh N voi 101^102.
tinh tong:
S=(1+2.5+3.5+...+101+201)+12+22+32+...1002)
tinh tong
1 + 2 + 22 + 23 +...+ 299 + 2100
Tinh G=1/3+2/3^2+3/3^3+...+100/3^100
tinh tong
\(S=\left(-3\right)^0+\left(-3\right)^1+\left(-3\right)^2+...+\left(-3\right)^{2014}\)
tinh S= 1+1/2(1+2)+1/3(1+2+3)+...+1/100(1+2+3+...+100)
tinh tong : 1+3+5+7+..997+999 (tinh bang 2 cach)
Tinh
A=1+1/2(1+2)+1/3(1+2+3)+...+1/100(1+2+3+...+100)
tổng 3 so =9, tong binh phuong cua chung =53. tinh tong cac tich cua 2 trong 3 so ay
