Question

Jumlah 10 suku pertama dari deret : 1/2 + 1 +3/2 + 2=

Answer 1

Sn = n/2 (2a+(n-1)b)
a = 1/2
b = 1- 1/2 = 1/2

S10 = 10/2 (2(1/2)+(10-1)1/2)
S10 = 5(1+9/2)
S10 = 5(11/2)
= 55/2

Answer 2

Diketahui:
Deret aritmatika
a = 1/2
b = 1 - 1/2
b = 1/2

Ditanyakan:
S₁₀

Penyelesaian:
Cari U₁₀
Un = a + (n - 1)b
U₁₀ = 1/2 + (10 - 1) 1/2
U₁₀ = 1/2 + 9/2
U₁₀ = 10/2
U₁₀ = 5

Cari S₁₀
Sn = n/2 (a + Un)
S₁₀ = 10/2 (a + U₁₀)
S₁₀ = 5 (1/2 + 5)
S₁₀ = 5 (1/2 + 10/2)
S₁₀ = 5 (11/2)
S₁₀ = 55/2
S₁₀ = 27,5