Evaluate `7+ 77+777+......`upto `n`

prove that 7 + 77 + 777 +...... + 777........._(n-digits) 7 = 7/81 (10^(n+1) - 9n - 10) for all n in N

prove that 7 + 77 + 777 +...... + 777........._(n-digits) 7 = 7/81 (10^(n+1) - 9n - 10) for all n in N

Find the sum of the sequence 7, 77, 777, 7777, ... to n terms.

Find the sum of the sequence 7, 77, 777, 7777, ... to n terms.

Find the sum of the sequence 7, 77, 777, 7777, ... to n terms.

Find the sum of the sequence 7, 77, 777, 7777, ... to n terms.

By using the Principle of Mathematical Induction, prove the following for all n in N : 7+77+777 +........ to n terms = 7/81 (10^(n+1)-9n-10) .

Find the sum of the sequence 7,77,777,7777,......to n terms.

Find the sum of the sequence 7, 77, 777, 7777, . . . to n terms.