To find the maximum value of sinx⋅cosx, use the double angle formula.
The double angle formula states:
sin(2x)=2sinxcosx
Rearranging:
sinxcosx=2sin(2x)
The sine function has a range of [−1,1].
Maximum value of sin(2x)=1
Therefore:
Maximum of sinxcosx=21
This maximum occurs when sin(2x)=1, which happens when 2x=2π, giving x=4π.
At x=4π:
sin(4π)⋅cos(4π)=21⋅21=21
The maximum value of sinx⋅cosx is 21.