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 Linear Algebra Linear Algebra Math Forum

 July 14th, 2019, 07:12 AM #1 Newbie   Joined: Jul 2019 From: Saudi Arabia Posts: 4 Thanks: 1 I need help I have two questions, they should be either true or false and I am asked to justify my answer. Thank you in advance.
 July 14th, 2019, 08:41 AM #2 Senior Member   Joined: Jun 2019 From: USA Posts: 309 Thanks: 160 Q1) A square matrix is singular if its determinant is zero (and vice versa). Find the determinant and see whether it equates to zero for all a, b, c. Q2) If I recall correctly, |AB| is equal to |A||B|. If that's true, then |B| = (|P|/|P|)|A| = |A|. Thanks from Canopus Last edited by skipjack; July 14th, 2019 at 08:13 PM.
 July 15th, 2019, 02:32 PM #3 Newbie   Joined: Jul 2019 From: Saudi Arabia Posts: 4 Thanks: 1 Thank you so much for the help! Thanks from DarnItJimImAnEngineer
 July 16th, 2019, 07:37 PM #4 Newbie   Joined: Jul 2019 From: Saudi Arabia Posts: 4 Thanks: 1 Hello, for Q1) My friend had the solution below: How did he come to this solution? I have tried to calculate the determinant but the unknowns made it a headache for me.
July 16th, 2019, 08:42 PM   #5
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Joined: Sep 2015
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Quote:
 Originally Posted by Canopus Hello, for Q1) My friend had the solution below: How did he come to this solution? I have tried to calculate the determinant but the unknowns made it a headache for me.
It's just standard Gaussian elimination

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 July 17th, 2019, 03:31 AM #6 Newbie   Joined: Jul 2019 From: Saudi Arabia Posts: 4 Thanks: 1 Thank you Boss!

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