Xin lỗi mk viết nhầm
12A=13101-1
=>\(A=\frac{13^{101}-1}{12}\)
A=130+131+132+133......+1399+13100.
13A = 131+132+133+134......+1399+13100+13101
13A - A = ( 131+132+133+134......+1399+13100+13101 ) - ( 130+131+132+133......+1399+13100. )
12A = 13101 - 130
A = \(\frac{13^{101}-13^0}{12}\)
Ta có
A=130+131+132+133+...+1399+13100
=>13A=131+132+133+134+...+13100+13101
=> 13A-A=(131+132+133+134+...+13100+13101)-(
130+131+132+133+...+1399+13100 )
=> 12A=130-13101=1-13101
=>\(A=\frac{1-13^{101}}{12}\)