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Paragraph: Suppose inverse of a matrix is defined as A⁻¹= A^T f(A) and A⁻¹ exists, where f(A)= |A^T | . Let A be an n^ t^h order matrix then Question: If |A| f(A) is the probability that the equation x^ n-1 +(2 n-1) x^n n! +(2 n+3) x^ n-1 +n=0 has exactly one real root then f(A)^n=x^ n+2 has

Options

  1. Atwo real roots and two imaginary roots
  2. Btwo real roots and one imaginary roots
  3. Cone real root and two imaginary roots
  4. Done real root and three imaginary roots

Correct answer

C. one real root and two imaginary roots

Step-by-step solution

aligned & A( adj A)=|A| I_n & A^ =f(A) A⁻¹ & |A^T |=f(A)^n |A⁻¹ | f(A)=f(A)^n |A⁻¹ | aligned But |A⁻¹ |= 1 |A| f(A)=f(A)^n 1 |A| |A|=f(A)^ n-1 | adj A|=|A|^ n-1 = [f(A)^ (n-1) ]^ (n-1) =f(A)^ (n-1)^2 ....(1) | adj adj A|=|A|^ (n-1)^2 .....(2) But from defimition |A|= |A^ |=f(A) aligned & |A|=f(A)^ = |A^ |=f(A) & n-1=1 & n=2 aligned From (1) and (2) A= adj A aligned & f(x)=x^3+ 5 x^2 2 +6 x+2 & f^ (x)=3 x^2+5 x+6 aligned aligned & D 0 & f^ (x) 0 x R aligned Graph for f(x) f ( x ) has only one real root aligned & p=1

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