Mì-chit-fûn-ho̍k

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Lióng-vi thu̍k-li̍p khok-li̍p Mì-chit-fûn thí-hì ke Sú-ho̍k-kâ： Ngie-sat-khiet Ngiù-tun Tsiok-sṳ lâu Kô-thi̍t-fut-lî-tet Lòi-pu-nì-tshṳ

Chú-yeu khói-ngiam

${\begin{aligned}f'(3)&=\lim _{h\to 0}{(3+h)^{2}-3^{2} \over {h}}\\&=\lim _{h\to 0}{9+6h+h^{2}-9 \over {h}}\\&=\lim _{h\to 0}{6h+h^{2} \over {h}}\\&=\lim _{h\to 0}(6+h)\\&=6.\end{aligned}}$