Question

Nomor 8 sama caranya

Answer 1

Verified answer

Mapel ; Matematika

1 + 3 + 5 + 7 + .... + 89

Un = a + (n - 1) b
89 = 1 + (n - 1) 2
89 = 1 + 2n - 2
89 - 1 + 2 = 2n
90 = 2n
45 = n

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

Sn = 45/2 (2(1) + (45 - 1) 2)
Sn = 22,5 (2 + 88)
Sn = 22,5 × 90
Sn = 2025




45 = n