Question 1059586
{{{a[1] = -5}}} and {{{a[n] = n - a[n-1]}}} are given to us.



First term: 
{{{a[1] = -5}}}
Given; no need to do any work here



Second term:
{{{a[n] = n - a[n-1]}}}
{{{a[2] = 2 - a[2-1]}}} Replace every n with 2
{{{a[2] = 2 - a[1]}}}
{{{a[2] = 2 - (-5)}}} Replace a1 with -5 (see above)
{{{a[2] = 2 + 5}}}
{{{a[2] = 7}}}
second term = 7



Third term:
{{{a[n] = n - a[n-1]}}}
{{{a[3] = 3 - a[3-1]}}} Replace every n with 3
{{{a[3] = 3 - a[2]}}} 
{{{a[3] = 3 - 7}}} Replace a2 with 7 (see above)
{{{a[3] = -4}}}
third term = -4



Fourth term:
{{{a[n] = n - a[n-1]}}}
{{{a[4] = 4 - a[4-1]}}} Replace every n with 4
{{{a[4] = 4 - a[3]}}}
{{{a[4] = 4 - (-4)}}} Replace a3 with -4 (see above)
{{{a[4] = 4 + 4}}}
{{{a[4] = 8}}}
fourth term = 8




Summary:
First term = -5
Second term = 7
Third term = -4
Fourth term = 8


The first four terms are: -5, 7, -4, 8