Nilai dari U1+U4 adalah...a. 8. c. 10. e. 16b. 9. d. 12

Nilai dari U1+U4 adalah…a. 8. c. 10. e. 16b. 9. d. 12

$a + {ar}^{2} = 10 : : : : : : a(1 + {r}^{2}) = 10 \ ar + {ar}^{3} = 5 : : : : : ar(1 + {r}^{2} ) = 5 \ frac{10}{a} = frac{5}{ar} \ r = frac{1}{2} \ a(1 + {( frac{1}{2} )}^{2} ) = 10 \ a(1 + frac{1}{4} ) = 10 \ a( frac{5}{4} ) = 10 \ a = 8 \ a + a {r}^{3} = 8 + 8. {( frac{1}{2} )}^{3} = 9$