Question

find (sn=2+22+222+..........n terms​

Answer 1

Step-by-step explanation:

2+22+222+2222+........ n terms

2(1+11+111+1111+....... n terms)

2(9+99+999+..........n terms)

9

2(10-1+10²-1+10³-1+10⁴-1+.......n terms)

9

2(10+10²+10³+.....nterms-1-1-1....n terms)

9

2(10+10²+10³+.....nterms-n)

9

2(10(10^n-1)-n)

9. (9)

2[10(10^n-1)-9n]

9[9]

2 (10(10^n-1)-9n)

81