octave:2> x=[10:100]; octave:3> y=-x; octave:4> loglog(x,y) octave:5> y=x; octave:6> loglog(x,y) octave:7> y=x^(-1); error: for A^b, A must be square error: evaluating binary operator `^' near line 7, column 4 error: evaluating assignment expression near line 7, column 2 octave:7> y=x.^(-1); octave:8> loglog(x,y) octave:9> x x = Columns 1 through 12: 10 11 12 13 14 15 16 17 18 19 20 21 Columns 13 through 24: 22 23 24 25 26 27 28 29 30 31 32 33 Columns 25 through 36: 34 35 36 37 38 39 40 41 42 43 44 45 Columns 37 through 48: 46 47 48 49 50 51 52 53 54 55 56 57 Columns 49 through 60: 58 59 60 61 62 63 64 65 66 67 68 69 Columns 61 through 72: 70 71 72 73 74 75 76 77 78 79 80 81 Columns 73 through 84: 82 83 84 85 86 87 88 89 90 91 92 93 Columns 85 through 91: 94 95 96 97 98 99 100 octave:10> n=[10,20,30,40]; octave:11> err=[1e-1,1e-1/2,1e-1/3,1e-1/4]; octave:12> loglog(n,err) octave:13> loglog(n,err,'*') octave:14> loglog(n,err,'*',n,n.^(-1)) octave:15> err=[1e-2,1e-2/2,1e-2/3,1e-2/4]; octave:16> loglog(n,err,'*',n,n.^(-1)) octave:17> loglog(n,err,'*',n,n.^(-1)/n(1).^(-1)*err(1)) octave:18> err=[1e-2,1e-2/4,1e-2/9,1e-2/16]; octave:19> loglog(n,err,'*',n,n.^(-1)/n(1).^(-1)*err(1)) octave:20> loglog(n,err,'*',n,n.^(-2)/n(1).^(-2)*err(1)) octave:21> diary off