I have researched this area a little bit and now I am a little worried because three different websites have gave me three different answers. Some functions matched, but others didn't. My general concensus is inverse Sin= 1 and 4 quad inverse Cos= 1 and 2 quad inverse tan= 1 and 4 quad inverse cotangent = 1 and 2 quad inverse secant= 1 and 2 quad inverse cosecant= 1 and 4 quad More importantly is there a quick way to verify this in your calculator? I tried giving random angles for the inverse functions in my calculator to the so called undefined quadrants for the directed inverse functions but I am not getting a light bulb here. So maybe a little help?