Jumlah deret tak hingga x – 1/5 x^2 + 3/25 x^3 – 9/125 x^4 + …. = 1/2, maka x=?
Jawaban Terkonfirmasi
Deret Geometri Tak Hingga
1/3 x – 1/5 x² + 3/25 x³ – 9/125 x⁴ + … = 1/2
a = 1/3 x
r = U2/U1
r = -1/5 x² / 1/3 x
r = -3/5 x
S~ = a/(1 – r)
1/2 = (1/3 x) / (1 + 3/5 x)
Kali silang
2/3 x = 1 + 3/5 x
2/3 x – 3/5 x = 1
1/15 x = 1
x = 15 ✔