Question

Evaluate
7+77+777+7777........upto n terms

Answer 1

I am stuck on a step

Answer 2

I got this

Answer 3

how?

Answer 4

@ganeshie8

Answer 5

Shall i tell my approach i am stuck on a step

Answer 6

yea please

Answer 7

\[\frac{ 7 }{ 9 }\left\{ 9 +99 +999+....... \right\}\]
\[\frac{ 7 }{ 9 }\left\{ (10-1) + (10^{2}-1)+..... \right\}\]

Answer 8

that looks great ! keep going

Answer 9

No i could have but i am stuck , i mean how should i procedd

Answer 10

group the exponents and 1's separately

Answer 11

and keep in mind that there are n terms

Answer 12

\[\frac{ 7 }{ 9 }\left\{ (10-1) + (10^{2}-1)+..... \right\}\]

\[\frac{ 7 }{ 9 }\left\{ (10 + 10^2 + \cdots 10^n) - (1 + 1 + \cdots \text{n terms})\right\}\]

Answer 13

\[\frac{ 7 }{ 9 }\left\{ (10 + 10^2 + \cdots 10^n) - n\right\}\]

Answer 14

if they are similar we can write them as "one"
Like n here?

Answer 15

1 + 1 = 2
1 + 1 + 1 = 3
1 + 1 + 1 + 1 = 4
1 + 1 + 1 + 1 + ... n times = n

Answer 16

now that can be done thanks a ton

Answer 17

can u plz help me after
@ganeshie8