Let x be a real number in the interval [−1,1].
(i) State the range of the function y=arcsinx and describe its monotonicity on its domain.
(ii) Using the property stated in part (i), prove that the inequality arcsinx>6π is equivalent to x>21.
(iii) Describe, without drawing, how the graph of y=arcsinx helps to visualise the result obtained in part (ii).