Deret:(1+2)+(2+3)+(3+4)+(4+5)+....+(24+25)= a.234 b.324. c.342. d.422
Matematika
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Pertanyaan
Deret:(1+2)+(2+3)+(3+4)+(4+5)+....+(24+25)=
a.234 b.324. c.342. d.422
a.234 b.324. c.342. d.422
1 Jawaban
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1. Jawaban newwiguna
(1+2)+(2+3)+(3+4)+(4+5)+....+(24+25)
= 3 + 5 + 7 + 9 + ... + 49
a = 3
b = 5 - 3 = 2
Un = 49
Un = a + (n-1)b
49 = 3 + (n-1)2
49 = 3 + 2n - 2
49 = 2n + 1
2n = 49 - 1
2n = 48
n = 24
Sn = n/2(a + Un)
S24 = 24/2(3 + 49)
S24 = 12 x 52
S24 = 624