Pêng-hong-kin

Tī sò͘-ha̍k siōng, sò͘-ba̍k a ê pêng-hong-kin (平方根) sī y, ah y ² = a. Iā tio̍h sī kóng, sò͘-ba̍k y ê pêng-hong téng-î a. Pí-lūn kóng, 4 hām -4 lóng sī 16 ê pêng-hong-kin, in-ūi 4² = (−4)² = 16. Só͘-ū hui-hū-sò͘ ê si̍t-sò͘ lóng ū chi̍t ê te̍k-tēng ê hui-hū-sò͘ pêng-hong-kin, hō-chò chú-pêng-hong-kin (主平方根), siá chò √a; kî-tiong √ chit-ê hû-hō hō-chò kin-hō. Pí-lūn kóng, 9 ê chú-pêng-hong-kin sī 3, siá chò √9 = 3, in-ūi 3² = 3 · 3 = 9, ah 3 sī hui-hū-sò͘.

Só͘-ū chiàⁿ-sò͘ lóng ū 2 ê pêng-hong-kin: √a hām −√a, mā ē-tàng chò-hóe siá chò ±√a (khòaⁿ chiàⁿ-hū-hō). Sui-jiân chú-pêng-hong-kin chí sī kî-tiong chi̍t ê pêng-hong-kin, m̄-koh it-poaⁿ "pêng-hong-kin" tio̍h sī teh kóng chú-pêng-hong-kin. Chiàⁿ-sò͘ a ê chú-pêng-hong-kin mā ē-tàng siá chò be̍k ūn-sǹg a^1/2.^[1]

Hū-sò͘ ê pêng-hong-kin sī ho̍k-cha̍p-sò͘ thó-lūn ê hoān-ûi.

Chham-khó

↑ Zill, Dennis G.; Shanahan, Patrick (2008). A First Course in Complex Analysis With Applications (2nd pán.). Jones & Bartlett Learning. p. 78. ISBN 0-7637-5772-1. Goân-pún bāng-ia̍h Pó-chûn tī 2016-09-01. Extract of page 78 Archived 2016-09-01 at the Wayback Machine.

[1] Zill, Dennis G.; Shanahan, Patrick (2008). A First Course in Complex Analysis With Applications (2nd pán.). Jones & Bartlett Learning. p. 78. ISBN 0-7637-5772-1. Goân-pún bāng-ia̍h Pó-chûn tī 2016-09-01. Extract of page 78 Archived 2016-09-01 at the Wayback Machine.

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