How do I find the maximum and minimum values of the function f(x) = x - 2 sin (x)f(x)=x2sin(x) on the interval [-pi/4, pi/2][π4,π2]?

1 Answer
Jan 30, 2015

You can derive your function and set your derivative equal to zero. The value(s) of xx you'll find will be the points of maxima or minima.

In your case you have:

f'(x)=1-2cos(x)

Setting f'(x)=0 gives:

1-2cos(x)=0
When x=pi/3

You can now analyze when the derivative is bigger than zero:

1-2cos(x)>0
i.e. when x>pi/3
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Your value of x=pi/3 represent a minimum for your function, and in your interval you get the graph:
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