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Question Number 171826 by Mikenice last updated on 21/Jun/22
if a+b+c=0,find the value of   (a^2 /(bc))+(b^2 /(ca))+(c^2 /(ab))
$${if}\:{a}+{b}+{c}=\mathrm{0},{find}\:{the}\:{value}\:{of}\: \\ $$$$\frac{{a}^{\mathrm{2}} }{{bc}}+\frac{{b}^{\mathrm{2}} }{{ca}}+\frac{{c}^{\mathrm{2}} }{{ab}} \\ $$
Answered by nimnim last updated on 21/Jun/22
(a^2 /(bc))+(b^2 /(ca))+(c^2 /(ab))  =((a^3 +b^3 +c^3 )/(abc))  =((a^3 +b^3 +c^3 )/(abc))−3+3  =((a^3 +b^3 +c^3 −3abc)/(abc))+3  =(((a+b+c)(a^2 +b^2 +c^2 −ab−bc−ca))/(abc))+3  =(((0)(a^2 +b^2 +c^2 −ab−bc−ca))/(abc))+3  =0+3  =3
$$\frac{{a}^{\mathrm{2}} }{{bc}}+\frac{{b}^{\mathrm{2}} }{{ca}}+\frac{{c}^{\mathrm{2}} }{{ab}} \\ $$$$=\frac{{a}^{\mathrm{3}} +{b}^{\mathrm{3}} +{c}^{\mathrm{3}} }{{abc}} \\ $$$$=\frac{{a}^{\mathrm{3}} +{b}^{\mathrm{3}} +{c}^{\mathrm{3}} }{{abc}}−\mathrm{3}+\mathrm{3} \\ $$$$=\frac{{a}^{\mathrm{3}} +{b}^{\mathrm{3}} +{c}^{\mathrm{3}} −\mathrm{3}{abc}}{{abc}}+\mathrm{3} \\ $$$$=\frac{\left({a}+{b}+{c}\right)\left({a}^{\mathrm{2}} +{b}^{\mathrm{2}} +{c}^{\mathrm{2}} −{ab}−{bc}−{ca}\right)}{{abc}}+\mathrm{3} \\ $$$$=\frac{\left(\mathrm{0}\right)\left({a}^{\mathrm{2}} +{b}^{\mathrm{2}} +{c}^{\mathrm{2}} −{ab}−{bc}−{ca}\right)}{{abc}}+\mathrm{3} \\ $$$$=\mathrm{0}+\mathrm{3} \\ $$$$=\mathrm{3} \\ $$$$ \\ $$
Commented by Mikenice last updated on 21/Jun/22
thanks sir
$${thanks}\:{sir} \\ $$

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