If A =[ 𝑐𝑜𝑠𝛼 𝑠𝑖𝑛𝛼 𝑠𝑖𝑛𝛼 𝑐𝑜𝑠𝛼 ] and A+𝐴 𝑇= 𝐼2 then 𝛼 is (𝑎)𝛼 = 𝑛𝜋 𝑛 - Applied Mathematics - Matrices

Question

If A =[ 𝑐𝑜𝑠𝛼
−𝑠𝑖𝑛𝛼
𝑠𝑖𝑛𝛼
𝑐𝑜𝑠𝛼 ] and A+𝐴 𝑇=
𝐼2 then 𝛼 is
(𝑎)𝛼 = 𝑛𝜋 𝑛 ∈
𝑍
(𝑏)(2𝑛 + 1) 𝜋 2 𝑛 ∈
𝑍
(𝑐)𝛼 = 2𝑛𝜋 + 𝜋 3 𝑛
∈ 𝑍
(d)None of these

Jalaj Juneja · Accepted Answer

If A =[ 𝑐𝑜𝑠𝛼 −𝑠𝑖𝑛𝛼 𝑠𝑖𝑛𝛼 𝑐𝑜𝑠𝛼 ] and A+𝐴 𝑇= 𝐼2 then 𝛼 is (𝑎)𝛼 = 𝑛𝜋 𝑛 ∈ 𝑍 (𝑏)(2𝑛 + 1) 𝜋 2 𝑛 ∈ 𝑍 (𝑐)𝛼 = 2𝑛𝜋 + 𝜋 3 𝑛 ∈ 𝑍 (d)None of these