The period of the function is π. Specifically, cos(x+Pi/3) can be expanded first, then multiplied by sinx, then reduced, and then converted into one. This is the routine practice of senior high school students at present.
If you can't, you can ask the teacher instead of asking questions all the time online. Baidu knows that it can't enter mathematical formulas, and it is still very painful to see the problem.
Specific process: You can copy the following code into mathtype software (the latest version is required).
\[f(x)= \ sin x \ cos \ left({ x+\ frac { \ pi } { 3 } } \ right)
= \ sin x \ left({ \ frac { 1 } { 2 } \ cos x-\ frac { { \ sqrt 3 } } { 2 } \ sin x } \ right)
= { 1 } { 2 } ^2}x
= \ frac { 1 } { 2 } \ left({ \ frac { 1 } { 2 } \ sin2x+\ frac { 3 } } { 2 } \ cos 2x } \ right)-\ frac { 3 } } { 4 }
= \ frac { 1 } { 2 } \ sin \ left({ 2x+\ frac { \ pi } { 3 } } \ right)-\ frac { { \ sqrt 3 } } { 4 } \]
So the minimum positive period is π.