WAEC - Mathematics (1995 - No. 7)
lf 16/9 , x, 1, y are in Geometric Progression (GP), find the product of x and y.
9/16
3/4
1
4/3
16/6
Explicació
16/9, x, 1, y => a, ar, ar2, ar3
ar2 = 1 => 16r2/9 = 1 => 16r2
9 => r2 = 9/16 => r = 3/4
ar2 = y = ar2 x r = 1 x 3/4 = 3/4
x xy = 4/3 x 3/4 = 1
ar2 = 1 => 16r2/9 = 1 => 16r2
9 => r2 = 9/16 => r = 3/4
ar2 = y = ar2 x r = 1 x 3/4 = 3/4
x xy = 4/3 x 3/4 = 1