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13.4: Приклади
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=\ frac {1} {2\ pi}\ int_ -a} ^ {a} д х e^ {-i k_ {x} x} =\ ліворуч. \ frac {1} {-2 i\ пі k_ {x}} e^ {-i k_ {x} x}\ право|_ {-a} ^ {a} =\ frac {\ sin k_ {x} a} {\ pi k_ {x}}. =\ frac {e^ {-i n б к_ {х...=\ frac {1} {2\ pi}\ int_ -a} ^ {a} д х e^ {-i k_ {x} x} =\ ліворуч. \ frac {1} {-2 i\ пі k_ {x}} e^ {-i k_ {x} x}\ право|_ {-a} ^ {a} =\ frac {\ sin k_ {x} a} {\ pi k_ {x}}. =\ frac {e^ {-i n б к_ {х}/2}\ ліворуч (e^ {i n b k_ {x}/2} -e^ {-i n b k_ {x}/2}\ праворуч)} {e^ {-i b k_ {x}/2}\ ліворуч (e^ {i b k_ {x}/ 2} -e^ {-i b k_ {x}/2}\ право)} =e^ {-i (n-1) b k_ {x}/2}\ frac {\ sin n b k_ {x}/2} {\ sin b k_ {x}/2}.