π Example 1. Find the sum of the sequence 7, 77, 777, 7777, β¦ to n terms.
β Solution: This is not a geometric sequence, however, we can relate it to a geometric sequence. by writing the terms as Sn=7+77+777+7777+β― to n terms
π Ex2. Find the sum to n terms of the sequence, 8, 88, 888, 8888, β¦
β Solution:
The given sequence is 8, 88, 888, 8888, β¦ . This sequence is not a geometric sequence. However, it can be changed to geometric sequence. by writing the terms as Sn=8+88+888+8888+β― to n terms
π Ex3. Find the sum of the following series up to n terms:
(i) 5+55+555+β― (ii) .6+.66+.666+β―
β Solution:
(i) 5+55+555+β―
Let Sn=5+55+555+β― to n terms
(ii) .6+.66+.666+β¦
Let Sn=06.+0.66+0.666+β― to n terms
