Question

Sn= 81+8181+818181+...+n terms. find Sn. (hint it is related to sum of gp)

Answer 1

Step-by-step explanation:

81+81+81+81+81..............sn

here a=81 and last

so sn formula

sn=81+81+81+81...........+81+81+

81+81+81+81+........81+81+81

=162++162+162+162+162.......+162+162

162*total number digit/number digit

Answer 2

Answer:

81+81+81+81+81 ......sn

a=81

Step-by-step explanation:

sn = 81+81+81+81........81+81

81+81+81+81........81+81

=162+162+162+162+162.....+162+162