If a, b, c are in AP and x, y, z are in GP then prove that the value of xb - c. yc - a. za - b is 1.
To prove: xb - c. yc - a. za - b = 1….(i)
It is given that a,b,c are in A.P.
⇒ 2b = a + c…(ii)
And x,y,z, are in G.P.
⇒ y2 = xz
⇒ x = y2/z
Substitute this value of x in equation (i),we get
L.H.S =
⇒
⇒
⇒
⇒
⇒ y0.z0…(Using equation (i))
= 1 = R.H.S
Hence, proved that . If a, b, c are in AP and x, y, z are in GP then xb - c. yc - a. za - b = 1