Find: cos 75∘sin 15∘+sin 12∘cos 78∘−cos 18∘sin 72∘= ____

1.	Find: cos 75∘sin 15∘+sin 12∘cos 78∘−cos 18∘sin 72∘= ______.
Answer» Find: $\frac{cos 75^{\circ}}{sin 15^{\circ}} + \frac{sin 12^{\circ}}{cos 78^{\circ}} - \frac{cos 18^{\circ}}{sin 72^{\circ}} =$ ______.

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