Math, asked by jshndip14, 5 months ago

sum the series 5 + 55 +555..... upto n term​

Answers

Answered by Anonymous
6

Answer:

ANSWER

Let S

n

=5+55+555+... to n terms.

Then,

s

n

=5(1+11+111+... to n terms)

⇒s

n

=

5

9

(9+99+999+... to n terms)

⇒S

n

=

9

5

{(10−1)+(10

2

−1)+(10

3

−1)+...+(10

n

−1)}

⇒S

n

=

9

5

{(10+10

2

+10

3

+...+10

n

)−n}

⇒S

n

=

9

5

{10(

10−1

10

n

−1

)−n}

⇒S

n

=

9

5

{

9

10

(10

n

−1)−n}=

81

5

(10

n+1

−9n−10).

Answered by covid20k
0

Answer:

hope this may be helpful

Attachments:
Similar questions