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In trigonometry, it is common to use mnemonics to help remember trigonometric identities and the relationships between the various trigonometric functions. For example, the ''sine'', ''cosine'', and ''tangent'' ratios in a right triangle can be remembered by representing them as strings of letters, for instance SOH-CAH-TOA in English: :Sine = Opposite ÷ Hypotenuse :Cosine = Adjacent ÷ Hypotenuse :Tangent = Opposite ÷ Adjacent One way to remember the letters is to sound them out phonetically (i.e. "SOH-CAH-TOA"). Another method is to expand the letters into a sentence, such as "Some Old Houses Can Always Hide Their Old Age".〔 A sentence that is more appropriate for high school is, "Some old horse came a'hopping through our alley." 〕 Communities exposed to Chinese dialect may choose to remember it as TOA-CAH-SOH, which also means 'big-footed woman' in Hokkien. ==Azal's Mnemonic== Azal's Mnemonic is an alternative mnemonic to ''SOH-CAH-TOA'' for people who have different names for the legs of a triangle, i.e. Perpendicular(P) for Opposite(O) and Base(B) for Adjacent(A). Azal's Mnemonic goes like this: Some People Have Curly Black Hairs Through Proper Brushing. Here, ''Some People Have'' is for Sine=Perpendicular/Hypotenuse, ''Curly Black Hairs'' is for Cosine=Base/Hypotenuse, and ''Through Proper Brushing'' is for Tangent=Perpendicular/Base. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mnemonics in trigonometry」の詳細全文を読む スポンサード リンク
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