已知tanx=2，(1)求(2/3)sin2x+(1/4)cos2x的值；(2)求2sin2x-sinxcosx+cos2x的值．
(1)(2/3)sin2x+(1/4)cos2x=[(2/3sin2x+(1/4)cos2x]/(sin2+cos2x)=[(2/3)tan2x+(1/4)]/(tan2x+1)=7/12；(2)2sin2x-sinxcosx+cos2x=(2sin2x-sinxcosx+cos2x)/(sin2x+cos2x)=(2tan2x-tanx+1)/(tan2x+1)=7/5
