carilah xn dari deret aritmatika 18+16+14...........jika n = 22
Matematika
sultan028
Pertanyaan
carilah xn dari deret aritmatika 18+16+14...........jika n = 22
1 Jawaban
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1. Jawaban newwiguna
mungkin maksudnya Sn...?
a = 18
b = 16 - 18 = -2
Sn = n/2(2a + (n-1)b)
S22 = 22/2 (2 . 18 + (22 - 1)(-2))
S22 = 11 (36 + (21 x (-2))
S22 = 11 (36 + (-42))
S22 = 11 (36 - 42)
S22 = 11 x -6
S22 = -66