Finding a tangent equation

The curve \(y=a\tan bx\) has period \(60^\circ\) and passes through \((15^\circ,4)\), where \(a>0\) and \(b\) is a positive integer.

1. Find \(a\) and \(b\).[3]
2. Sketch the curve for \(-30^\circ<x<30^\circ\), showing its asymptotes and the given point.[2]