Let \( P(x, y, z) \) be a point in the first octant, whose projection in the \( xy \)-plane is the point \( Q \). Let \( OP = \gamma \); the angle between \( OQ \) and the positive \( x \)-axis be \( \theta \); and the angle between \( OP \) and the positive \( z \)-axis be \( \phi \), where \( O \) is the origin. Then the distance of \( P \) from the \( x \)-axis is:
