If a, b, c, d are in G.p., prove that :
(i) (a2+b2),(b2+c2),(c2+d)2 are in G.P.
(ii) (a2−b2),(b2−c2),(c2−d)2 are in G.P.
(iii) 1a2+b2,1b2+c2,1c2+d2 are in G.P.
(iv) (a2+b2+c2),(ab+bc+cd),(b2+c2+d2)
If a + b + c = 2s, then prove the following identities
(a) s2 + (s − a)2 + (s − b)2 + (s − c)2 = a2 + b2 + c2
(b) a2 + b2 − c2 + 2ab = 4s (s − c)
(c) c2 + a2 − b2 + 2ca = 4s (s − b)
(d) a2 − b2 − c2 + 2ab = 4(s − b) (s − c)
(e) (2bc + a2 − b2 − c2) (2bc − a2 + b2 + c2) = 16s (s − a) (s − b) (s − c)
(f)