What is the domain of #f(x)=cosx#?

1 Answer
Mar 23, 2018

Domain of #f(x)# is #RR#. See below

Explanation:

#f(x)=cosx# is a circular function defined in the goniometric circle by #x# coordinate. Thus is defined for all positions in that circle. But #f(x)# repeat his values each lap. For this reason, we say #cosx# is a periodic function. See the graph graph{cosx [-12.66, 12.65, -6.33, 6.33]}

The range of #cosx# is (as we can see in graph) #[-1,1]#