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The maximum value of sinxcosx\sin x \cdot \cos x is:

Solution

Correct Option: 2

To find the maximum value of sinxcosx\sin x \cdot \cos x, use the double angle formula.

The double angle formula states:

sin(2x)=2sinxcosx\sin(2x) = 2\sin x \cos x

Rearranging:

sinxcosx=sin(2x)2\sin x \cos x = \frac{\sin(2x)}{2}


The sine function has a range of [1,1][-1, 1].

Maximum value of sin(2x)=1\sin(2x) = 1

Therefore:

Maximum of sinxcosx=12\sin x \cos x = \frac{1}{2}


This maximum occurs when sin(2x)=1\sin(2x) = 1, which happens when 2x=π22x = \frac{\pi}{2}, giving x=π4x = \frac{\pi}{4}.

At x=π4x = \frac{\pi}{4}:

sin(π4)cos(π4)=1212=12\sin\left(\frac{\pi}{4}\right) \cdot \cos\left(\frac{\pi}{4}\right) = \frac{1}{\sqrt{2}} \cdot \frac{1}{\sqrt{2}} = \frac{1}{2}


The maximum value of sinxcosx\sin x \cdot \cos x is 12\frac{1}{2}.

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