Find the local maxima and local minima, if any, of the following functions. Find also the local maximum and the local minimum values, as the case may be:

f (x) = sin x – cos x, 0 < x < 2π


f (x) = sin x – cos x, 0 < x < 2π

f’(x) = cosx + sinx


Now, f’(x) = 0


cosx + sinx = 0


cosx = -sinx


tanx = -1



’(x) = -sinx + cosx



Then, by second derivative test,


is point of local maxima and the local maximum value of f at is



And,


is point of local minima and the local minimum value of f at is



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