Here's the question you clicked on:
moongazer
graphing inverse trig functions
why is when you want to graph the inverse, you make it y=x?
http://openstudy.com/users/moongazer#/updates/504c2818e4b0925ffedd278c
this might help http://www.regentsprep.org/Regents/math/algtrig/ATT8/inversetrig.htm and when you graph the inverse it is y = x because that is just the rule for it.