help plz...
a,b,c in geometrical progression.. a^2+b^2+c^2=S^2 a+b+c=qS show that 1/3<q^2<3
@ganeshie8
a,b,c in geometrical progression.. does that mean a b=ar c=ar^2 ?
yes
yes @ikram002p
ok then \( \large a^2+a^2r^2+a^2r^4=s^2\) \( \large a^2(1+ r^2+ r^4)=s^2\) \(\large a+b+c=qs\) \(\large a+ar+ar^2=qs\) \(\large a(1+r+r^2)=qs\) \(\large a^2(1+r+r^2)^2 =q^2s^2\) thus \(\large q^2=\dfrac { a^2(1+r+r^2)^2 }{s^2} \) \(\large q^2=\dfrac { a^2(1+r+r^2)^2 }{a^2(1+ r^2+ r^4) } \) \(\large q^2=\dfrac { (1+r+r^2)^2 }{(1+ r^2+ r^4) } \)
mmm lets see how to go far from this
we know r\(\neq 0\) r\(\neq 1\) so \(0<r<1\) or \(1<r\)
mmm idk how to continue xD since i got \(q^2>3\) for \(r>1\) xD
ok ill go through this part \(0<r<1\) \(0<r^2<1\) \(0<r^4<1\) but \(0<r^4<r^2<r <1\) mmm
have no clue what the rest would be , sry
Join our real-time social learning platform and learn together with your friends!