

InterviewSolution
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If A is a square matrix, using mathematical induction prove that (AT)n = (An)T for all n ϵ N. |
Answer» Given, A is a square matrix. We need to prove that (AT)n = (An)T. We will prove this result using the principle of mathematical induction. Step 1 : When n = 1, we have ∴ (AT)1 = AT Hence, The equation is true for n = 1. Step 2 : Let us assume the equation true for some n = k, Where k is a positive integer. ⇒ (AT)k = (Ak)T To prove the given equation using mathematical induction, we have to show that, (AT)k+1 = (Ak+1)T. We know, (AT)k+1 = (Ak+1)T ⇒ (AT)k+1 = (Ak)T × AT We have, (AB)T = BTAT. ⇒ (AT)k+1 = (Ak)T ⇒ (AT)k+1 = (A1+k)T ∴ (AT)k+1 = (Ak+1)T Hence, The equation is true for n = k + 1 under the assumption that it is true for n = k. Therefore, By the principle of mathematical induction, the equation is true for all positive integer values of n. Thus, (AT)n = (An)T for all n ϵ N. |
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