## Trigonometry 7th Edition

$78^{\circ}$ $\cot 12^{\circ} = \tan 78^{\circ}$
$\cot 12^{\circ} = \tan 78^{\circ}$ Reason- cotangent and tangent are cofunctions and $12^{\circ} + 78^{\circ} = 90^{\circ}$ i.e. $12^{\circ}$ and $78^{\circ}$ are complementary angles.