
Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
The answers and hints for quiz 6 of math 121, which was held on november 16, 2006. It includes the solutions for finding the product of two matrices, solving a system of linear equations using matrix inverses, and evaluating a sum.
Typology: Quizzes
1 / 1
This page cannot be seen from the preview
Don't miss anything!
Math 121, Quiz 6, 16 November 2006
Name: Hints and Answers
. Find the following, if possible, if an operation is not possible, state why it is not possible. (a) AB (b) BA
Answer. (a) Not possible because the number of columns of A is 3 which is not equal to the number of rows of B which is 2. (b) BA exists and is found as follows
BA =
x + y + 2 z = − 2 2 x + 3 y + 3 z = 3 3 x + 3 y + 7 z = − 1
Solve this system using the fact that the inverse of
(^) is
Answer. Multiply the inverse of A by the matrix of constants as follows:
x y z
Thus the solution is x = − 24 , y = 12, z = 5.
k=
2 k − 1.
Answer.
k=
2 k − 1 = 2(3) − 1 + 2(4) − 1 + 2(5) − 1 = 5 + 7 + 9 = 21.