Question

Mohon bantuannya sobat ...
Deret geometri U5=9/2, U7=9/8, Tent. a dan r!

Answer 1

Un = a r^n-1

U7/U5 = (a r^6) / (a r^4)
(9/8) : (9/2) = r²
9/8 x 2/9 = r²
r = 1/2

U5 = 9/2
a r^4 = 9/2
a (1/2)^4 = 9/2
a (1/16) = 9/2
a = 9/2 x 16
a = 72