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Copyright © 2012-2015 Manabu Kano. All rights reserved. 1 京都学学部物学科 業数学F2(フーリエ解析) 京都大学大学院情報学研究科システム科学専攻 Human Systems Lab., Dept. of Systems Science Graduate School of Informatics, Kyoto University 工業数学F2 #4 フーリエ級数を極める 京都大学 加納 復習1:複素フーリエ級数 2 周期 2π の周期関数 f(x) の複素フーリエ級数展開 複素フーリエ係数 オイラーの公式 レオンハルト・オイラー(Leonhard Euler1707-1783

工業数学F2 - 加納学@京都大学大学院情報学研究科 ...manabukano.brilliant-future.net/lecture/appliedmathF2/...Title 工業数学F2-04(ウェブ用).pptx Author

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  • Copyright 2012-2015 Manabu Kano. All rights reserved. 1

    F2

    Human Systems Lab., Dept. of Systems Science Graduate School of Informatics, Kyoto University

    #4

    2

    2 f(x)

    Leonhard Euler 1707-1783

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 2

    F2

    3

    cn n |cn|

    4

    x

    f (x)

    2TT0-T

    a

    -10 -8 -6 -4 -2 0 2 4 6 8 10

    -10 -8 -6 -4 -2 0 2 4 6 8 10

    x0

    -

    1

    -1

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 3

    F2

    5

    cn c0 cn

    in in

    Outline 6

    l l l l l l

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 4

    F2

    7

    bn an n -n

    8

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 5

    F2

    9

    x2

    --20

    f (x)

    x = 0

    10

    x M

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 6

    F2

    11

    x 1 M x M

    12

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 7

    F2

    13

    N > M

    Z b

    a

    NX

    n=1

    gn(x)dxZ b

    ag(x)dx

    =

    Z b

    a

    NX

    n=1

    gn(x) g(x)!dx

    Z b

    a

    NX

    n=1

    gn(x) g(x)

    dx Z b

    adx = (b a)

    14

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 8

    F2

    15

    Outline 16

    l l l l l l

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 9

    F2

    17

    n -n

    18

    bn an

    n -n

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 10

    F2

    bn an

    19

    n -n

    a0/2

    20

    bn an

    bn ana0/2

    n, -n

    n, -n

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 11

    F2

    Outline 21

    l l l l l l

    22

    f (x) x f (x)

    Dirichlet 1805-1859

    f (x) f (x)

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 12

    F2

    23

    l f (x)

    l f (x) f(x) xz0

    f (x) lim!0 f(z )

    lim!0

    f(z + )

    Outline 24

    l l l l l l

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 13

    F2

    25

    Gibbs 1839-1903

    -2

    -1

    0

    1

    2

    26

    l n n f (x) n

    Sn(x) n f*(x)

    n Sn(x) f (x)

    -2

    -1

    0

    1

    2

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 14

    F2

    -2

    -1

    0

    1

    2

    n

    27

    x0

    f (x)

    1

    Outline 28

    l l l l l l

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 15

    F2

    29

    2 f (x) TN(x)

    E cn, dn

    (1) 30

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 16

    F2

    (2) 31

    cn, dn

    32

    cn, dn f (x)

    N N f (x)

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 17

    F2

    33

    Bessel 1784-1846

    = 0

    34

    f (x) N

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 18

    F2

    35

    36

    f (x) 2 f (x)

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 19

    F2

    37

    38

    2 f (x) f (x) E N 0 f (x)

    limit in the mean

  • Copyright 2012-2015 Manabu Kano. All rights reserved. 20

    F2

    Outline 39

    l l l l l l

    40