MATLAB程序设计与应用第二版课后题答案.doc

第二章 3.设矩阵A为 A=[24 23 9 21 6;65 74 24 11 21;34 5 98 75 21;8 42 42 53 121;43 21 45 64 21]; B=A(2:5,1:2:5) B = 65 24 21 34 98 21 8 42 121 43 45 21 （2）A(7)=[] A = 24 65 34 8 43 23 5 42 21 9 24 98 42 45 21 11 75 53 64 6 21 21 121 21 （3）A+30 （4）size(A);ndims(A) （5）题目有误 （6）reshape(x,3,4) （7）abs(x) （8）char(x) 4. L1 = 0 0 0 0 1 0 0 0 0 L2 = 1 1 1 1 1 0 0 0 0 L3 = 0 0 0 1 1 1 0 0 0 L4 = 4 5 6 5.(1)B=A(1:3,:) C=A(:,1:2) D=A(2:4,3:4) E=B*C B = 23.0000 10.0000 -0.7780 0 41.0000 -45.0000 65.0000 5.0000 32.0000 5.0000 0 32.0000 C = 23.0000 10.0000 41.0000 -45.0000 32.0000 5.0000 6.0000 -9.5400 D = 65.0000 5.0000 0 32.0000 54.0000 3.1400 E = 1.0e+003 * 0.9141 -0.2239 1.2080 2.7123 1.1330 -0.2103 (2)ED ans = 0 1 0 0 0 1 ED ans = 1 1 0 1 1 1 E|D ans = 1 1 1 1 1 1 ~D|~E ans = 0 0 1 0 0 0 find(A=10A25) ans = 1 5 6. all(A) ans = 0 any(A) ans = 1 isnan(A) ans = 0 1 0 0 0 0 0 isinf(A) ans = 0 0 1 1 0 0 0 isfinite(A) ans = 1 0 0 0 1 1 1 7. A(1).x1=’学号’;A(1).x2=’姓名’;A(1).x3=’专业’;A(1).x4.x41=’成绩1’;………. A(2).x1=’学号’;A(2).x2=’姓名’;A(2).x3=’专业’;A(2).x4.x41=’成绩1’;………. A(3).x1=’学号’;A(3).x2=’姓名’;A(3).x3=’专业’;A(3).x4.x41=’成绩1’;………. A(4).x1=’学号’;A(4).x2=’姓名’;A(4).x3=’专业’;A(4).x4.x41=’成绩1’;………. A(5).x1=’学号’;A(5).x2=’姓名’;A(5).x3=’专业’;A(5).x4.x41=’成绩1’;………. 8. (1) size(B) ans = 2 2 ndims(B) ans = 2 (2) B(2) ans = [3x3 double B(4) ans = {3x3 cell} (3) B(3)=[] B = [1] [3x3 double] {3x3 cell} B{3}=[] B = [1] [3x3 double] [] 第三章 1. (1)A=eye(3) (2) A=100+100*rand(5,6) (3)A=1+sqrt