Question

what. will be the answer

Answer 1

hello!
$(a + b + c {)}^{2} = {a}^{2} + {b}^{2} + {c}^{2} + 2(ab + bc + ca) \\ \\ now \: put \: the \: value \\ \\ (2 {)}^{2} = 1 + 2(ab + bc + ca) \\ \\ 2(ab + bc + ca) = 4 - 1 \\ (ab + bc + ca) = \frac{3}{2} \\ \\ now \\ \frac{1}{a} + \frac{1}{b} + \frac{1}{c} = \\ \\ = > take \: lcm \\ \\ = \frac{bc + ca + ab}{abc} \\ putting \: value \\ = \frac{ \frac{3}{2} }{3} \\ \\ = \frac{3}{2 \times 3} = \frac{1}{2} \: ans$