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**TsAmE** f(x) = sinx + cosx, 0 <= x <= 2pi

a) Find the intervals on which f is increasing or decreasing.

b) Find the local maximum and minimum values of f

c) Find the intervals of concavity and the inflection points.

a)For f'(x) I got my critical points to be x = pi / 4 and x = 5pi / 4 but didnt know how to put this on a sign table in order to find when it is inc/dec

b) f(pi / 4) = (2)^1/2, but I didnt know how to work out

f(5pi / 4) = sin(5pi / 4) + cos(5pi / 4) without a calculator

c)For f''(x) my critical points were x = 3 pi / 4 and x = 3 pi / 2 and had the same problem as a)