Homework Help

If a 4x4 matrix A with rows v_1,v_2,v_3 and v_4 has determinant det(a) = -8, then...

user profile pic

chocobob | Student | Honors

Posted April 28, 2013 at 1:04 AM via web

dislike 1 like

If a 4x4 matrix A with rows v_1,v_2,v_3 and v_4 has determinant det(a) = -8, then det[[2v_1+8v_3],[v_2],[9v_1+3v_3],[v_4]] = ???????

Tagged with linear algebra, math

1 Answer | Add Yours

user profile pic

tiburtius | High School Teacher | (Level 3) Associate Educator

Posted April 28, 2013 at 6:14 AM (Answer #1)

dislike 0 like

`det[[2v_1+8v_3],[v_2],[9v_1+3v_3],[v_4]]=`

Adding one row multiplied by scalar to another row does not change the value of determinant.

`det[[2v_1],[v_2],[3v_3],[v_4]]=`

Multiplying a row by a scalar multiplies a whole determinant by that scalar.

`2cdot3cdotdet[[v_1],[v_2],[v_3],[v_4]]=6cdot(-8)=-48` <--Solution

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes