Respuesta :
Answer:
[tex]\sum_{x=1}^{4}(17-4n)[/tex]
Step-by-step explanation:
The given expression is
[tex]13+9+5+1[/tex]
The terms of this series are
13,9,5,1
It is an AP. Here, first term is 13 and common ratio is -4.
The nth term of an AP is
[tex]a_n=a+(n-1)d[/tex]
where, a is first term and d is common difference.
The nth term of given AP is
[tex]a_n=13+(n-1)(-4)[/tex]
[tex]a_n=13-4n+4[/tex]
[tex]a_n=17-4n[/tex]
The summation formula of an AP is
[tex]\sum_{x=1}^{n}a_n[/tex]
The value of n is 4 because the number of term is 4. So, the summation formula is
[tex]\sum_{x=1}^{4}(17-4n)[/tex]
