Please reply sir. This question is killing me.From :Piyush Bohra

Dear Piyush, in inverse trigonometric functions there are certain range and domains in which the function is defined unlike simple trigonometric functions. Otherwise they contradict basic property of a function (one value for one point). For example Sin-1 has range [-pi/2 , pi/2] and domain [-1, 1] and Cos-1 has range [0,pi] and domain [-1 , 1].
In this domain Cos-1 is decreasing therefore if Cos-1x > p. Then x p. Then, x > Sinp. Here is cos-1 graph. Please approve this answer if it cleared your query.