“SOHCAHTOA” 是一個有用的助記符，用於記住三角函式 正弦、餘弦 和 正切 的定義，即，正弦等於對邊比斜邊，餘弦等於鄰邊比斜邊，正切等於對邊比鄰邊。
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其他助記符包括
1. "Tommy On A Ship Of His Caught A Herring" (可能在英國比美國更常見)。
2. "Oscar Has A Hold On Angie."
3. "Oscar Had A Heap of Apples."
4. "The Old Army Colonel And His Son Often Hiccup" (這給出了函式以正切、餘弦、正弦的順序)。
5. "Studying Our Homework Can Always Help To Obtain Achievement."
6. "Some Old Hippy Caught Another Hippy Tripping On Acid."
