Question

Dari suatu barisan aritmatika u 2 + 7 = 26 dan u3 + u5 = 22 . Tentukan suku ke 100 ?

Answer 1

U2+ U7 = (a + b) + (a+6b)
26 = 2a+7b

U3 + U5 = (a+2b) + (a+4b)
22 = 2a + 6b

26 = 2a+7b
22 = 2a + 6b
---------------------(-)
4 = b

22 = 2a + 6b
22 = 2a + 6.4
-2 = 2a
a = -1

U100= a + 99b
U100 = -1 + 99.4 = 395