How do you write the first five terms of the geometric sequence #a_1=5, r=-1/10#?

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Answer 1 · 2017-04-21T08:06:39

#" "5" "-0.5," "0.05," "-0.005," "0.0005#

The General term is #T_n = an^(n-1)#

Option 1.: Let #n = 1,2,3,4,5 # and calculate each term.

Option 2: Multiply one term by #-1/10# to get the next.
This seems the easier option.

#5 xx -1/10= -0.5#

#-0.5 xx-1/10 = 0.05# and so on,

This gives: #" "5" "-0.5," "0.05," "-0.005," "0.0005#

Notice the sign changes each time.