Answers

2015-06-14T15:14:33+05:30
A+b+c=0
⇒(a+b+c)²=a²+b²+c²+2(ab+bc+ca) 
Since a+b+c=0 , (a+b+c)²=0
⇒a²+b²+c²+2(ab+bc+ca)=0
⇒a²+b²+c²=-2(ab+bc+ca)
 \frac{a^{2}+b^{2}+c^{2}  }{ab+bc+ca} = -2
Ans: \frac{a^{2}+b^{2}+c^{2} }{ab+bc+ca} = -2
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