Determine the interval, where f(x)=sin x - cos x, 0<x<2pie is strictly increasing or decreasing?

For *f* (*x*) to be increasing* f'*(*x*) > 0

∴ *f *(*x*) increases in the interval

For *f *(*x*) to be decreasing, *f*'(*x*) < 0

∴ *f *(*x*)decreases in the interval

∴ *f *(*x*) increases in the interval and decreases in the interval

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