If a, b, c are three consecutive terms of an AP and x, y, z are three consecutive terms of GP, then the value of xb - c yc - a za - b is
If a, b, c are three consecutive terms of an AP and x, y, z are three consecutive terms of GP, then the value of xb - c yc - a za - b is Correct Answer 1
Concept:
If a, b, c and three consecutive terms of an AP then b - a = c - b = d (Common difference)
If x, y, z are three consecutive terms of GP then y2 = xz
Calculations:
Given, a, b, c and three consecutive terms of an AP.
⇒ b - a = c - b = d(Common difference)
So, a = a
b = a + d
c = a + 2d
Now, c - a = 2d, a - b = -d, b - c = -d
x, y, z are three consecutive terms of GP
⇒ y2 = xz
Now, consider xb - c yc - a za - b
= x-d yc - a z -d
= (xz) -d y2d
= (y2) -d y2d ( ∵y 2 = xz)
= y-2d y2d
= y0
= 1
Hence, If a, b, c and three consecutive terms of an AP and x, y, z are three consecutive terms of GP, then the value of xb - c yc - a za - b = 1