Find the missing terms of the arithmetic sequence.​ (Hint: The arithmetic mean of the first and fifth terms is the third​ term.)
3​, a 2​, a 3​, a 4​, negative 13​, ...

Respuesta :

Answer:

The arithmetic sequence is: 3, -1, -5, -9, -13

Step-by-step explanation:

Recall that the nth term of an arithmetic sequence is defined via the formula:

[tex]a_n=a_1+(n-1)\,d[/tex]

where d is the common difference, n is the term number, and [tex]a_1[/tex] is the first term.

Since we know what the first and fifth terms are (3 and -13 respectively), we can find the common difference and with it any of the missing terms:

[tex]a_n=a_1+(n-1)*d\\a_5=a_1+(5-1)*d\\-13=3+(4)*d\\-16=4*d\\d=-\frac{16}{4} \\d=-4[/tex]

now that we know d=-4, we can find the missing terms:

[tex]a_2=3+(2-1)*(-4) = -1\\a_3=3+(3-1)*(-4)= -5\\a_4=3+(4-1)*(-4)=-9[/tex]

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