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Simultaneous Linear Equations

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Presentation on theme: "Simultaneous Linear Equations"— Presentation transcript:

1 Simultaneous Linear Equations http://nm.mathforcollege.com

2 The size of matrix A. B. C. D. is 10 http://nm.mathforcollege.com

3 The c 32 entity of the matrix A. 2 B. 3 C. 6.3 D. does not exist 10 http://nm.mathforcollege.com

4 Given then if [C]=[A]+[B], c 12 = A.0 B.6 C.12 10 http://nm.mathforcollege.com

5 Given then if [C]=[A]-[B], c 23 = A. -3 B. 3 C. 9 http://nm.mathforcollege.com

6 Given then if [C]=[A][B], then c 31 =. A.-57 B.-45 C.57 D.does not exist 10 http://nm.mathforcollege.com

7 A square matrix [A] is lower triangular if A. B. C. D. 10 http://nm.mathforcollege.com

8 A square matrix [A] is upper triangular if 1. 2. 3. 4. http://nm.mathforcollege.com

9 An example of upper triangular matrix is A. B. C. D. none of the above http://nm.mathforcollege.com

10 An example of lower triangular matrix is A. B. C. D. none of the above http://nm.mathforcollege.com

11 An identity matrix [I] needs to satisfy the following A. B. C. D. all of the above matrix is square 10 http://nm.mathforcollege.com

12 Given then [A] is a matrix. A.diagonal B. identity C. lower triangular D.upper triangular http://nm.mathforcollege.com

13 A square matrix is diagonally dominant if 1. 2. 3. 4. http://nm.mathforcollege.com

14 The following system of equations x + y=2 6x + 6y=12 has solution(s). 1.no 2.one 3.more than one but a finite number of 4.infinite 10 http://nm.mathforcollege.com

15 PHYSICAL PROBLEMS http://nm.mathforcollege.com

16 Truss Problem http://nm.mathforcollege.com

17 Pressure vessel problem a b a b c http://nm.mathforcollege.com

18 Polynomial Regression We are to fit the data to the polynomial regression model http://nm.mathforcollege.com

19 END http://nm.mathforcollege.com

20 Simultaneous Linear Equations Gaussian Elimination (Naïve and the Not That So Innocent Also) http://nm.mathforcollege.com

21 The goal of forward elimination steps in Naïve Gauss elimination method is to reduce the coefficient matrix to a (an) _________ matrix. A.diagonal B. identity C. lower triangular D. upper triangular http://nm.mathforcollege.com

22 One of the pitfalls of Naïve Gauss Elimination method is A.large truncation error B.large round-off error C.not able to solve equations with a noninvertible coefficient matrix http://nm.mathforcollege.com

23 Increasing the precision of numbers from single to double in the Naïve Gaussian elimination method A.avoids division by zero B.decreases round-off error C.allows equations with a noninvertible coefficient matrix to be solved http://nm.mathforcollege.com

24 Division by zero during forward elimination steps in Naïve Gaussian elimination for [A][X]=[C] implies the coefficient matrix [A] 1.is invertible 2.is not invertible 3.cannot be determined to be invertible or not http://nm.mathforcollege.com

25 Division by zero during forward elimination steps in Gaussian elimination with partial pivoting of the set of equations [A][X]=[C] implies the coefficient matrix [A] 1.is invertible 2.is not invertible 3.cannot be determined to be invertible or not http://nm.mathforcollege.com

26 Using 3 significant digit with chopping at all stages, the result for the following calculation is A.-0.0988 B.-0.0978 C.-0.0969 D.-0.0962 http://nm.mathforcollege.com

27 Using 3 significant digits with rounding-off at all stages, the result for the following calculation is A.-0.0988 B.-0.0978 C.-0.0969 D.-0.0962 http://nm.mathforcollege.com

28 Simultaneous Linear Equations LU Decomposition http://nm.mathforcollege.com

29 You thought you have parking problems. Frank Ocean is scared to park when __________ is around. A.A$AP Rocky B.Adele C.Chris Brown D.Hillary Clinton http://nm.mathforcollege.com

30 Truss Problem http://nm.mathforcollege.com

31 Determinants If a multiple of one row of [A] nxn is added or subtracted to another row of [A] nxn to result in [B] nxn then det(A)=det(B) The determinant of an upper triangular matrix [A] nxn is given by Using forward elimination to transform [A] nxn to an upper triangular matrix, [U] nxn. http://nm.mathforcollege.com

32 If you have n equations and n unknowns, the computation time for forward substitution is approximately proportional to A.4n B.4n 2 C.4n 3 http://nm.mathforcollege.com

33 If you have a n x n matrix, the computation time for decomposing the matrix to LU is approximately proportional to A.8n/3 B.8n 2 /3 C.8n 3 /3 http://nm.mathforcollege.com

34 LU decomposition method is computationally more efficient than Naïve Gauss elimination for solving A.a single set of simultaneous linear equations B.multiple sets of simultaneous linear equations with different coefficient matrices and same right hand side vectors. C.multiple sets of simultaneous linear equations with same coefficient matrix and different right hand side vectors http://nm.mathforcollege.com

35 For a given 1700 x 1700 matrix [A], assume that it takes about 16 seconds to find the inverse of [A] by the use of the [L][U] decomposition method. Now you try to use the Gaussian Elimination method to accomplish the same task. It will now take approximately ____ seconds. A.4 B.64 C.6800 D.27200 http://nm.mathforcollege.com

36 For a given 1700 x 1700 matrix [A], assume that it takes about 16 seconds to find the inverse of [A] by the use of the [L][U] decomposition method. The approximate time in seconds that all the forward substitutions take out of the 16 seconds is A.4 B.6 C.8 D.12 http://nm.mathforcollege.com

37 The following data is given for the velocity of the rocket as a function of time. To find the velocity at t=21s, you are asked to use a quadratic polynomial v(t)=at 2 +bt+c to approximate the velocity profile. t(s)01415203035 vm/s0227.04362.78517.35602.97901.67 A. B. C. D. http://nm.mathforcollege.com

38 Three kids-Jim, Corey and David receive an inheritance of $2,253,453. The money is put in three trusts but is not divided equally to begin with. Corey’s trust is three times that of David’s because Corey made and A in Dr.Kaw’s class. Each trust is put in and interest generating investment. The total interest of all the three trusts combined at the end of the first year is $190,740.57. The equations to find the trust money of Jim (J), Corey (C) and David (D) in matrix form is A. B. C. D. http://nm.mathforcollege.com

39 THE END http://nm.mathforcollege.com

40 4.09 Adequacy of Solutions http://nm.mathforcollege.com

41 The well or ill conditioning of a system of equations [A][X]=[C] depends on the A.coefficient matrix only B.right hand side vector only C.number of unknowns D.coefficient matrix and the right hand side vector http://nm.mathforcollege.com

42 The condition number of a n×n diagonal matrix [A] is A. B. C. D. http://nm.mathforcollege.com

43 The adequacy of a simultaneous linear system of equations [A][X]=[C] depends on (choose the most appropriate answer) A. condition number of the coefficient matrix B. machine epsilon C. product of the condition number of coefficient matrix and machine epsilon D. norm of the coefficient matrix

44 If http://nm.mathforcollege.com, then in [A][X]=[C], at least these many significant digits are correct in your solution, A. 0 B. 1 C. 2 D. 3

45 THE END http://nm.mathforcollege.com

46 Consider there are only two computer companies in a country. The companies are named Dude and Imac. Each year, company Dude keeps 1/5 th of its customers, while the rest switch to Imac. Each year, Imac keeps 1/3 rd of its customers, while the rest switch to Dude. If in 2003, Dude had 1/6 th of the market and Imac had 5/6 th of the marker, what will be share of Dude computers when the market becomes stable? 1. 37/90 2. 5/11 3. 6/11 4. 53/90 http://nm.mathforcollege.com


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