if a, b , c are in GP. prove that a2 + b2, ab+ bc, b2 + c2are also in GP

As we are given a, b,c are in G.P lets assume, a=br; b=b; c=brWhere rcommon ratio between the terms such that ratio of cb=baNow, we calculate value of a2 + b2, ab+ bc, b2 + c2 to prove that these are in G.P1st term=a2 + b2=br2+b2=b21+r2r22nd term ab+ bc=br×b+b×br=b21+r2r3rd term b2 + c2=b2+b2r2=b21+r23rd term2nd term=b21+r2b21+r2r=b21+r2×rb21+r2=r  12nd term1st term=b21+r2r×r2b21+r2=r     2From eq 1 & 2common ratios are same so a2 + b2, ab+ bc, b2 + c2 in G.P  Answer

  • 18
Nice question. I solved it and got a part of ab+bc =a+c. it may solve further...
  • 7
as upper answer is mine next you should use b^2=a×c. then from this u can prove (a+c)^2=(b^2+c^2)(a^2+c^2)and put value of a+c and make in simple form of ba=cb. so here comes a,b,c are in gp as b^2
=a×c
  • 2
What are you looking for?