Now by definition
_1/2[pi]
2 / z^2 z^4 z^6
J0(z) = ---- | cos(z cos[theta])d[theta] = --- + ------- - ----------- + ... (11).
[pi] _/0 2^2 2^2.4^2 2^2.4^2.6^2
Encyclopaedia Britannica, 11th Edition, "Diameter" to "Dinarchus" Volume 8, Slice 4 · 第 56 / 86 题