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Matrices and Determinants question

2025 · 28 Jan · Shift 1 · Q46
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Matrices and Determinants question

2025 · 28 Jan · Shift 1 · Q46

JEE MainMathematicsMatrices and DeterminantsNumerical+4 / −1
Let M denote the set of all real matrices of order 3×33 \times 33×3 and let S={−3,−2,−1,1,2}\mathrm{S}=\{-3,-2,-1,1,2\}S={−3,−2,−1,1,2}. Let S1={A=[aij]∈M:A=AT and aij∈ S,∀i,j},S2={A=[aij]∈M:A=−AT and aij∈ S,∀i,j},S3={A=[aij]∈M:a11+a22+a33=0 and aij∈ S,∀i,j}.\begin{aligned} & \mathrm{S}_1=\left\{\mathrm{A}=\left[a_{\mathrm{ij}}\right] \in \mathrm{M}: \mathrm{A}=\mathrm{A}^{\mathrm{T}} \text { and } a_{\mathrm{ij}} \in \mathrm{~S}, \forall \mathrm{i}, \mathrm{j}\right\}, \\ & \mathrm{S}_2=\left\{\mathrm{A}=\left[a_{\mathrm{ij}}\right] \in \mathrm{M}: \mathrm{A}=-\mathrm{A}^{\mathrm{T}} \text { and } a_{\mathrm{ij}} \in \mathrm{~S}, \forall \mathrm{i}, \mathrm{j}\right\}, \\ & \mathrm{S}_3=\left\{\mathrm{A}=\left[a_{\mathrm{ij}}\right] \in \mathrm{M}: a_{11}+a_{22}+a_{33}=0 \text { and } a_{\mathrm{ij}} \in \mathrm{~S}, \forall \mathrm{i}, \mathrm{j}\right\} . \end{aligned}​S1​={A=[aij​]∈M:A=AT and aij​∈ S,∀i,j},S2​={A=[aij​]∈M:A=−AT and aij​∈ S,∀i,j},S3​={A=[aij​]∈M:a11​+a22​+a33​=0 and aij​∈ S,∀i,j}.​ If n(S1∪S2∪S3)=125αn\left(S_1 \cup S_2 \cup S_3\right)=125 \alphan(S1​∪S2​∪S3​)=125α, then α\alphaα equls ‾\underline{\hspace{2cm}}​.
Numerical answer
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