3d Geometry

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