3.已知函數(shù)y=
,記該函數(shù)圖象為G.
(1)當(dāng)m=2時(shí),
①已知M(4,n)在該函數(shù)圖象上,求n的值;
②當(dāng)0≤x<2時(shí),求函數(shù)G的最大值.
(2)當(dāng)m>0時(shí),作直線x=
m與x軸交于點(diǎn)P,與函數(shù)G交于點(diǎn)Q,若∠POQ=45°時(shí),求m的值;
(3)當(dāng)0≤m≤3時(shí),設(shè)圖象與x軸交于點(diǎn)A,與y軸交于點(diǎn)B,過點(diǎn)B作BC⊥BA交直線x=m于點(diǎn)C,設(shè)點(diǎn)A的橫坐標(biāo)為a,C點(diǎn)的縱坐標(biāo)為c,若a=-3c,求m的值.