Find an equation for the nth term of the arithmetic sequence.
a19 = -92, a20 = 6
Solution:
It is given that in an arithmetic sequence,
a19 = -92, a20 = 6
So, Common difference = d
d = a20 - a19
d = 6 - (-92)
d = 6 + 92
d = 98
We know that the formula for nth term an = a1 + (n - 1)d
Substitute the value of n = 20
a20 = a1 + (20 - 1)d
6 = a1 + 19(98)
6 = a1 + 1862
6 - 1862 = a1
-1856 = a1
a1 = -1856
Now nth term:
an = a1 + (n - 1)d
an = -1856 + (n - 1)98
an = -1856 + 98(n - 1)
Therefore, an = -1856 + 98(n - 1) is an equation for the nth term of the arithmetic sequence.
Find an equation for the nth term of the arithmetic sequence.
a19 = -92, a20 = 6
Summary:
an = -1856 + 98(n - 1) is an equation for the nth term of the arithmetic sequence. a19 = -92, a20 = 6.
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