I have some problems, help Solve the following nonhomogeneous system of linear equations: <mta

varitero5w

varitero5w

Answered question

2022-06-11

I have some problems, help
Solve the following nonhomogeneous system of linear equations:
x 1 + 2 x 2 + 3 x 3 + x 4 = 4 , 2 x 1 + 2 x 2 + 3 x 3 + x 4 = 5 , 3 x 1 + 3 x 2 + 4 x 3 + x 4 = 6
Please enter the specific solution first and then the basis in the space of solutions of the corresponding homogeneous system.
Comment of the teacher
Example. If x s = ( 0 1 0 1 ) is a specific solution and { ( 1 2 3 / 2 4 ) , ( 0 2 2 9 ) } is a basis of { x : A x = 0 } then please enter
[0,1,0,1],[1,2,3/2,4],[0,-2,2,9]
There is an automated system here, checking the solution.
Solution
Augmented matrix:
( 1 2 3 1 4 2 2 3 1 5 3 3 4 1 6 )
I managed to transform the augmented matrix to the diagonal form:
( 1 0 0 0 1 0 1 0 1 3 0 0 1 1 3 )
So, the specific solution is the last row + 0 at the bottom: x s = ( 1 3 3 0 ) . I checked, and it is really a solution of the original problem.
1-st equation:
1 1 + 2 ( 3 ) + 3 3 + 1 0 = 1 6 + 9 = 4
2-nd equation:
2 1 + 2 ( 3 ) + 3 3 + 1 0 = 2 6 + 9 = 5
3-rd equation:
3 1 + 3 ( 3 ) + 4 3 + 1 0 = 3 9 + 12 = 6
But, why does the basis in the comment consist of 2 columns? I think, it must be only 1: ( 0 1 1 1 ) - the 4-th column of the diagonal matrix and the last element (-1) is an element of negated identity matrix.
When I tried this solution: [1, -3, 3, 0],[0, -1, 1, -1] for the first time, the automated checker said: "incorrect". Then I wrote this question; but before posting it, I tried it again, and it said: "correct". Probably, I made a typo first time
How can I check, that
( 0 1 1 1 )
is really the basis of the space of solutions, like I did, validating the specific solution?

Answer & Explanation

Hadley Cunningham

Hadley Cunningham

Beginner2022-06-12Added 20 answers

I'm not sure if the teacher's comment was for specifically this question, but you're right. The solution to this system lies on a line and not a plane as the teacher's comment suggests.
To check that your answer is correct, substitute the general form back into the system. Here's an example with the first equation:
x 1 + 2 x 2 + 3 x 3 + x 4 = 4
1 + 2 ( 3 + x 4 ) + 3 ( 3 x 4 ) + x 4 = 4
1 6 + 9 + 3 x 4 3 x 4 = 4
4 = 4

Do you have a similar question?

Recalculate according to your conditions!

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?