NCERT Question

Asked by RACHIT_MAHAAN | 7th Sep, 2010, 03:15: PM

Expert Answer:

a,b,c,d are in G.Pa,b,c in G.P so b2=ac-------------(1)b,c,d in G.P so c2=bd--------------(2)From above 2 relations bc = ad---------(3)T.P.T (a2+b2+c2)(b2+c2+d2)=(ab+bc+cd)2R.H.S = (ab+bc+cd)2=a2b2+b2c2+c2d2+2ab2c+2bc2d+2abcd                                            = a2b2+b2c2+c2d2+2a2c2+2b2d2+2abcd                                                                                                  using (1) and (2)L.H.S = (a2+b2+c2)(b2+c2+d2)             = a2d2+(b2+c2)2+(b2+c2)(a2+d2)             =b2c2+(ac+bd)2 +(a2b2+a2c2+b2d2+c2d2)   by (1),(2) (3)             = b2c2+(a2c2+2abcd+b2d2)+(a2b2+a2c2+b2d2+c2d2)            = a2b2+b2c2+c2d2+2a2c2+2b2d2+2abcd            = R.H.S">

Answered by  | 9th Sep, 2010, 07:27: AM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.