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三角星形線的兩條互相垂直的法線的交點在哪里?Construct two mutually orthogonal tangents of the deltoid. Where do they meet?2三角星形線的兩條互相垂直的切線的交點在哪里?Construct the part of the tangent of the deltoid intercepted by the curve....

“星形線”的英語可以翻譯為：astroid，asteroid ...