MATLAB练习例子五(解方程)

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解线性方程 》 A = pascal(3) A = 1 1 1 1 2 3 1 3 6 》 B = magic(3) B = 8 1 6 3 5 7 4 9 2 》 C = fix(10*rand(3,2)) C = 9 4 2 8 6 7 》 u = [3; 1; 4] u = 3 1 4 》 v = [2 0 -1] v = 2 0 -1 》 s = 7 s = 7 》 x = A\u x = 10 -12 5 》 X = A\B X = 19 -3 -1 -17 4 13 6 0 -6 》 t = [0 .3 .8 1.1 1.6 2.3]' t = 0 0.3000 0.8000 1.1000 1.6000 2.3000 》 y = [.82 .72 .63 .60 .55 .50]'; 》 y y = 0.8200 0.7200 0.6300 0.6000 0.5500 0.5000 》 E = [ones(size(t)) exp(-t)] E = 1.0000 1.0000 1.0000 0.7408 1.0000 0.4493 1.0000 0.3329 1.0000 0.2019 1.0000 0.1003 》 c = E\y c = 0.4760 0.3413 》 T = (0:0.1:2.5)'; 》 Y = [ones(size(T)) exp(-T)]*c; 》 plot(T,Y,'-',t,y,'o') 》
Underdetermined Systems 》 R = fix(10*rand(2,4)) R = 0 8 1 1 3 0 2 6 》 b = fix(10*rand(2,1)) b = 2 1 》 format rat 》 p = R\b p = 0 11/48 0 1/6 》 Z = null(R,'r') Z = -2/3 -2 -1/8 -1/8 1 0 0 1 》 Inverses 》 A = pascal(3) A = 1 1 1 1 2 3 1 3 6 》 d = det(A) d = 1 》 X = inv(A) X = 3 -3 1 -3 5 -2 1 -2 1 》 B = magic(3) B = 8 1 6 3 5 7 4 9 2 》 d = det(B) d = -360 》 X = inv(B) X = 53/360 -13/90 23/360 -11/180 1/45 19/180 -7/360 17/90 -37/360
》 A = pascal(6) A = 1 1 1 1 1 1 1 2 3 4 5 6 1 3 6 10 15 21 1 4 10 20 35 56 1 5 15 35 70 126 1 6 21 56 126 252 Cholesky Factorization 》 R = chol(A) R = 1 1 1 1 1 1 0 1 2 3 4 5 0 0 1 3 6 10 0 0 0 1 4 10 0 0 0 0 1 5 0 0 0 0 0 1 》 B = magic(3) B = 8 1 6 3 5 7 4 9 2 LU Factorizaion 》 [L,U] = lu(B) L = 1.0000 0 0 0.3750 0.5441 1.0000 0.5000 1.0000 0 U = 8.0000 1.0000 6.0000 0 8.5000 -1.0000 0 0 5.2941 》 C = fix(10*rand(3,2)) C = 9 4 2 8 6 7 QR Factorization 》 [Q,R] = qr(C) Q = -0.8182 0.3999 -0.4131 -0.1818 -0.8616 -0.4739 -0.5455 -0.3126 0.7777 R = -11.0000 -8.5455 0 -7.4817 0 0 》 [Q,R] = qr(C,0) Q = -0.8182 0.3999 -0.1818 -0.8616 -0.5455 -0.3126 R = -11.0000 -8.5455 0 -7.4817 》 [Q,R,P} = qr(C) ??? [Q,R,P} | "]"、または "}" が見つからない、または表記が正しくありません 》 [Q,R,P] = qr(C) Q = -0.3522 0.8398 -0.4131 -0.7044 -0.5285 -0.4739 -0.6163 0.1241 0.7777 R = -11.3578 -8.2762 0 7.2460 0 0 P = 0 1 1 0 》 [Q,R,P] = qr(C,0) Q = -0.3522 0.8398 -0.7044 -0.5285 -0.6163 0.1241 R = -11.3578 -8.2762 0 7.2460 P = 2 1
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