5+9+13+17 +.... s20=
Matematika
Ayunimaulidina2007
Pertanyaan
5+9+13+17 +.... s20=
1 Jawaban
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1. Jawaban kembangapi
a=5
b=U2-U1=9-5=4
Sn=n/2(2a+(n-1)b)
S20=10(2×5+19×4)
S20=10(10+76)
S20=860