Carilah n jika : a. 1 + 2 + 3 + .... n =55
Matematika
DafaBuxx
Pertanyaan
Carilah n jika :
a. 1 + 2 + 3 + .... n =55
a. 1 + 2 + 3 + .... n =55
2 Jawaban
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1. Jawaban subebe
a = 1
b = 1
Sn = n/2 (2 + (n-1)1)
55 = n/2 (2 + n -1)
110 = n(n + 1)
110 = n^2 + n
n^2 + n - 110 = 0
(n - 10) (n+11) = 0
n = 10 -
2. Jawaban xkuadratz
1 + 2 + 3 + .... n =55
Sn = 1/2.n(n+1)
55 = 1/2.n(n+1)
110 = n²+n
n²+n-110 = 0
(n-10)(n+11) = 0
n-10 = 0
n = 10