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If a + b + c = m and $$\frac{1}{a}$$ + $$\frac{1}{b}$$ + $$\frac{1}{c}{\text{,}}$$ then average of a2, b2, c2 is?
Answer & Solution
Correct Answer:
Option
B
$$\eqalign{
& a + b + c = m \cr
& \Rightarrow \frac{1}{a} + \frac{1}{b} + \frac{1}{c} = 0 \cr
& \Rightarrow \frac{{ab + bc + ca}}{{abc}} = 0 \cr
& \Rightarrow ab + bc + ca = 0 \cr
& {\left( {a + b + c} \right)^2} = {\text{ }}{a^2} + {b^2} + {c^2} + 2\left( {ab + bc + ca} \right) \cr
& \Rightarrow {m^2} = {\text{ }}{a^2} + {b^2} + {c^2} \cr
& \Rightarrow \frac{{{m^2}}}{3} = {\text{ }}\frac{{{a^2} + {b^2} + {c^2}}}{3} \cr} $$
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