(1)y=1/2•PB•BC•sin∠B=1/2•x•4√(3/)3•√(3)/2
∴y=X(0≤x≤4√(3)/3)
(2)把y=√(3)/3代入
√(3)/3=X=BP
AP=4√(3)/3-√(3/)3=√(3)