Find the points of local maxima or local minima, if any, of the following functions, using the first derivative test. Also, find the local maximum or local minimum values, as the case may be:

f(x) = sin 2x, 0 < x < π

We have, f(x) = sin 2x


Differentiate w.r.t x, we get,


f ‘(x) = 2cos 2x, 0 < x,π


For, the point of local maxima and minima,


f ’(x) = 0


= 2x =


= x =


At x = f ’(x) changes from –ve to + ve


Since, x = is a point of Maxima


At x = f ‘ (x) changes from –ve to + ve


Since, x = is point of Minima.


Hence, local max value f = 1


local min value f = – 1


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