1.

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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