State the domain for which the inverse function is decreasing.

Don't really understand this question...

4 answers

inverse function of y=cosx (which is y=cos^-1(x))
if you look at the unit circle

cosine decreases continuously from zero to π
take a look at the graph. it increases on [-1,1] but you need to restrict the domain of cos(x) to [-π,0] or [π,2π], etc.
oops. my bad. I read "increasing"