(1)若sinB=2sinA三角形ABC中a/sinA=b/sinB因为SinB=2sinA所以sinB/sinA=2=b/a即b=2acosC=(a^2+b^2-c^2)/(2ab)c=2,cosC=60°,b=2a带入上式有1/2=(5a^2-4)/(2*2a^2)解得a=2√3/3,b=4√3/3(2)若三角形abc的面积等于√3S...