tan15度＋cot15度
=sin15°/cos15°+cos15°/sin15°
=(sin15°sin15°+cos15°cos15°)/(sin15°cos15°)
=2(sin15°sin15°+cos15°cos15°)/(2sin15°cos15°)
=2/(sin30°)
=2/(1/2)
=4
tan15度＋cot15度
=sin15°/cos15°+cos15°/sin15°
=(sin15°sin15°+cos15°cos15°)/(sin15°cos15°)
=2(sin15°sin15°+cos15°cos15°)/(2sin15°cos15°)
=2/(sin30°)
=2/(1/2)
=4