If you have arcsecx= pi/2 - arccot(sqrt(x^(2) -1) How do you actually show that these are equal to eah other. What we're told at the start of the question is thatonly constant functions have derivative zero at every point of an interval, and using that idea we're to show the relation aobe. Then as a hine we're told to try the values of arcesx and arccot (sqrt(x^(2) -1) when x =sqrt 2 To start with I've worked out the drivatives of the two functions, getting 1 over x sqrt(x^(2) - 1) and the same thing again only the negaive respectively. Can you give me a hint as to where I should be going with this question? Thanks!