MATH 220 FINAL EXAMINATION December 13, Name ID # Section #

Transcription

1 MATH 22 FINAL EXAMINATION December 3, 2 Name ID # Section # There are??multiple choice questions. Each problem is worth 5 points. Four possible answers are given for each problem, only one of which is correct. When you solve a problem, note the letter next to the answer that you wish to give and blacken the corresponding space on the answer sheet. Mark only one choice; darken the circle completely (you should not be able to see the letter after you have darkened the circle). THE USE OF CALCULATORS DURING THE EXAMINATION IS FORBIDDEN. CHECK THE EXAMINATION BOOKLET BEFORE YOU START. THERE SHOULD BE?? PROBLEMS ON?? PAGES (INCLUDING THIS ONE).

2 MATH 22 FINAL EXAMINATION PAGE 2. What is the solution of following system of equations x + 2x 2 + x 3 = 2x + x 2 2x 3 = 3 x + 3x 2 x 3 = 4? a) x = x 3, x 2 =, x 3 is free. b) x = + x 2, x 2 is free, x 3 =. c) x = x 2 + x 3, and x 2, x 3 are free. d) x = 2x 2 x 3, and x 2, x 3 are free. 2. Which of the following matrices is in echelon form (but not necessarily reduced echelon form)? a) b) c) d)

3 MATH 22 FINAL EXAMINATION PAGE 3 3. What geometric figure is formed from the span of the vectors 2, 5,? 4 9 a) a point. b) a line. c) a plane. d) all of R Which of the following sets of vectors span R 3? A = 2, 2, 3 B = 2, C = 2, 3,, 2 a) A only b) B only c) A and B d) A and C

4 MATH 22 FINAL EXAMINATION PAGE For what value(s) of h is the system with augmented matrix consistent? 2 h 6 a) It is consistent for all real h. b) It is consistent only if h = 8. c) It is consistent if h 8. d) It is never consistent. 6. Suppose A is a matrix with three rows. Three of the following statements are equivalent. Which statement is not equivalent to the others? a) The columns of A span R 3. b) A has exactly 3 pivots. c) A has a pivot in each column. d) Ax = b has a solution for all b R 3.

5 MATH 22 FINAL EXAMINATION PAGE 5 7. If the augmented matrix of a system of linear equations has the reduced echelon form shown below 2 3 2, then what is the set of solutions of the system? a) x = x 3 2 b) x = x 3 2 c) x = x + x 3 2 d) x = x 3 2

6 MATH 22 FINAL EXAMINATION PAGE 6 8. Find all values of h such that the set S = 2,, h 2 is linearly dependent. a) b) c) 2 d) 3 9. If T : R 2 R 2 is the linear transformation which first reflects points in the x -axis and then rotates points in the counterclockwise direction through π/2 radians, then what is the standard matrix of T? a) b) c) d)

7 MATH 22 FINAL EXAMINATION PAGE 7. If T is the linear transformation defined by the formula 2 3 T(x) = Ax, where A =, then which of the following statements is true? a) T is one to one and onto b) T is one to one, but it is not onto c) T is not one to one, but it is onto d) T is neither one to one nor onto. If A =, then what is the second row of A? a) [ ] b) [ ] c) [ ] d) [ ]

8 MATH 22 FINAL EXAMINATION PAGE 8 2. Which of the following is a subspace of R 3? a) The null space of a 3 4 matrix. b) The column space of a 4 3 matrix. c) V = x x 2 : x + x 2 x 3 d) W = x x 2 : 4x x 2 = x 3 3. If A = 3 2 then what is the dimension of the column space of A? a) b) c) 2 d) 3

9 MATH 22 FINAL EXAMINATION PAGE What is the determinant of the matrix ? h 3 + 5h 5 + 2h + 9h a) b) 6 c) 2 d) 8 5. If A = 2 3, then what are the eigenvalues of A? 3 6 a) 2 and 3. b) 3 and 7. c) 5 and 4. d) 2 and 3.

10 MATH 22 FINAL EXAMINATION PAGE 6. Suppose A and B are n n matrices. Which of the following statements is always true? a) If A and B are similar, then they have the same eigenvectors. b) If A and B are similar, then det(a + B) = det(a) + det(b). c) If A and B are similar, then they have the same eigenvalues. d) If A and B are similar, then they are diagonalizable. 7. If λ is the eigenvalue of an n n matrix A and x is the corresponding eigenvector, then which of the following statements is always true? a) x is in the null space of A λi. b) x is in the null space of A. c) x is in the column space of A λi. d) The column space of A λi is all of R n.

11 MATH 22 FINAL EXAMINATION PAGE 8. If A, B and C are 3 3 matrices such that det(a) = 2, det(b) = 3 and det(c) = 4, then what is det(2ab T C )? a) 3 b) 6 c) 2 d) 3/2 9. If A = 6, then which of the following is a matrix P such that P 3 8 AP is diagonal? a) P =, b) P =, c) P =, 2 2 d) P =.

12 MATH 22 FINAL EXAMINATION PAGE 2 [ 3 2. If y = and u =, then what is the distance from y to the line through u and the 4] 2 origin? a) 5 b) 2 5 c) 3 5 d) If W is the subspace of R 3 spanned by the orthogonal vectors v = and v 2 = and if y = 2 3, then what is the orthogonal projection of y onto W? a) v 2v 2 b) 2v v 2 c) 2v + 2 v 2 d) v + 2 v 2

13 MATH 22 FINAL EXAMINATION PAGE if x =,x 2 =, and x 3 =, then find an orthogonal set whose span is the same as the span of x,x 2 and x 3. a) b) c) d) /2 /4, /2, /4 3/4 /2, /2 /2, /2 3/4, /4, /4 /2, /2,

14 MATH 22 FINAL EXAMINATION PAGE Find the least squares solution ˆx of Ax = b when A = and b =. /2 a) ˆx = /2 /3 b) ˆx = /3 [ c) ˆx = ] d) ˆx = /3 /2 24. What is an orthogonal matrix U that diagonalizes the symmetric matrix a) U = 2 b) U = [ ] c) U = [ ] d) U = ? 2 3

15 MATH 22 FINAL EXAMINATION PAGE What is the matrix of the quadratic form 5x 2 8x x 2 7x 2 2? a) b) c) d)