What is the explicit formula for the sequence? 3, 1, –1, –3, –5, . . .

Question

-2n+3
n-5
2n-5
-2n+5

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Answer 1 · 2017-04-03T20:45:39

#-2n+5#

if by the explicit formula you mean the #n#th term, then it is #-2n+5#.

#3,1,-1,-3,-5# is a linear sequence; the difference between each number is constant.
#1=3=-2#
#(-1)-1=-2#
difference = #-2#

the difference is the coefficient of #n#, so the #n#th term is #-2n+#another number.

#n:1, 2,3,4#
#s:3,1,-1,-3#

first term:
#n=1#
#-2n=-2#
#3-(-2)=(+)5#

#therefore n#th term = #-2n+5#