If A =[a ij ] is a skew-symmetric matrix of order n, then

(a) a ij = 1/a ji  ∀ 𝑖,𝑗  

(b) a ij ≠ 0 ∀ 𝑖,𝑗

(c) a ij = 0, 𝑀ℎπ‘’π‘Ÿπ‘’ 𝑖 = 𝑗

(d) a ij ≠ 0 𝑀ℎπ‘’π‘Ÿπ‘’ 𝑖 = j

 

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Question 1 If A =[π‘Ž_𝑖𝑗 ] is a skew-symmetric matrix of order n, then (a) π‘Ž_𝑖𝑗 = 1/π‘Ž_𝑗𝑖 βˆ€ 𝑖,𝑗 (b) π‘Ž_𝑖𝑗 β‰  0 βˆ€ 𝑖,𝑗 (c) π‘Ž_𝑖𝑗 = 0, π‘€β„Žπ‘’π‘Ÿπ‘’ 𝑖 = 𝑗 (d) π‘Ž_𝑖𝑗 β‰  0 π‘€β„Žπ‘’π‘Ÿπ‘’ 𝑖 = j In a In a skew symmetric matrix A’ = βˆ’A For example If A = [β– 8(0&2&βˆ’3@βˆ’2&0&βˆ’9@3&9&0)] A’ = [β– 8(0&βˆ’2&3@2&0&9@βˆ’3&βˆ’9&0)] ∴ A’ = βˆ’A So, A is a skew symmetric matrix Now, We note that in every skew symmetric matrices Diagonal elements are zero i.e. a11 = 0, a22 = 0, a33 = 0 Thus, we can say that 𝒂_π’Šπ’‹ = 0, π‘€β„Žπ‘’π‘Ÿπ‘’ 𝑖 = 𝑗 So, the correct answer is (c)

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo