(1)因为 P是AB上的动点
所以 0＜|AP|≤|AB|
即0＜x≤4
(2)因为 S△APQ=12 S△ABC
S△APQ=(1/2)|AP||AQ|sinA = (1/2)xysinA
S△ABC=(1/2)|AB||AC|sinA = (1/2)*4*2*sinA
所以 (1/2)xysinA = (1/2)*(1/2)*4*2*sinA
即 xy = 4
y = 4/x (0＜x≤4)
函数图像的解答,各路英雄麻烦过来看看
(1)因为 P是AB上的动点
所以 0＜|AP|≤|AB|
即0＜x≤4
(2)因为 S△APQ=12 S△ABC
S△APQ=(1/2)|AP||AQ|sinA = (1/2)xysinA
S△ABC=(1/2)|AB||AC|sinA = (1/2)*4*2*sinA
所以 (1/2)xysinA = (1/2)*(1/2)*4*2*sinA
即 xy = 4
y = 4/x (0＜x≤4)