Soal dan Kunci Jawaban Matematika Kelas XII SMA - Barisan dan Deret

b. Sn = n/2(a + l) = 12/2(7 + 34) = 252

Soal 2:

S_n = a(1-r^n)/1-r = 4(1-2^7)/1-2 = 60

Soal 3:

a. Un = 3 + 3(n-1)

b. Sn = 100/2(3 + 3(100-1)) = 15150

Soal 4:

Sn = n/2(2a + (n-1)d) = 50/2(10 + (50-1)3) = 7750

Soal 5:

S_n ≥ 127