(1) sin A-2cos A=0,则sinA=2cosA所以tanA=sinA/cosA=2(2).f（x）=cos 2x+tan Asin x=cos 2x+2sin x=1-2sin²x+2sinx=-2(sin²x-sinx+1/4)+1/2+1=-2(sinx-1/2)²+3/2因为-1≤sinx≤1所以-3/2≤sinx-1/2...