Attempt any one of the following:
a. Show that the function f given by f(x)=tan−1(sinx+cosx), x>0 is always a strictly increasing function in (0,4π)
b. An open box is to be constructed by removing equal squares from each corner of a 3 metre by 8 metre rectangular sheet of aluminium and folding up the sides. Find the volume of the largest such box.