Answer with explanation:
The given Trigonometric function is:

You can write it as also:→ x= cos y
1.It is the inverse of Cosine function.
2. The Domain and range of this Real valued function is
Domain=Set of values taken by ,x for which y is defined.→x=[-1,1]
Range =Set of values taken by , y for which x is defined.→y=[0, π]
3. It decreases from 0 to π then increases from π to 2π.