Question

Tolong dijwbnya bsk dikpul
terima kasih

Answer 1

5) Sn pascal = 2^n-1
    S8 = 2^8-1 = 2^7 = 128(b)
6) persegi panjang = n(n+1)
    Sn = n/2 (a+Un)
    S10 = 10/2 [(1 x (1+1) + (10 x (10+1)
    S10 = 5 [(1 x 2) + (10 x 11)]
    S10 = 5 (2 + 110)
    S10 = 5 (112)
    S10 = 560(d)
7) a = 3
   b = 3
Sn = n/2 (2a + (n-1)b)
S10 = 10/2 [( 2 x 3) + (10-1)3]
S10 = 5 [6 + (9 X 3)
S10 = 5 (6 + 27)
S10 = 5(33) = 165(D)

8) a = 2
   b = 4
Sn = n/2 (2a+(n-1)b)
S15 = 15/2 [(2 x 2) + (15-1)4]
S15 = 7,5 (4 + (14 x 4)
S15 = 7,5 (4 + 56)
S15 = 7,5(60) = 450(C)

9) a = 20
    b = -3

S10 = 10/2 [(2 X 20) + (10-1)-3)
S10 = 10/2 (40 + (9 X -3)
S10 = 5 (40 + -27)
S10 = 5 (13) = 65(B)

10) Cari beda


cari suku awal
U3 = a + 2b
U3 = a + (2 x 4)
10 = a + 8
a = 10-8
a = 2

Ssehingga a =2, b = 4
S15 = 15/2 [(2 x 2) + (15-1)4]
S15 = 7,5 [4 + (14 X 4)
S15 = 7,5 (4 + 56)
S15 = 7,5 (60) = 450(B)