三角形的面积 = 1/2 ab sinC = 1/2ab 根号3 / 2 = 根号3 ab = 4 cos C = (a^2+b^2-c^2) / (2ab) = 1/2 a^2+b^2 = 8 a = 2,b = 2 sin B = 2 sin A a / sinA = b / sin B a = b/2 cos C = (a^2+b^2-c^2) / (2ab) = 1/2 a= 2根号3 / 3 b = 4根号3 / 3 三角形ABC的面积 = 1/2 ab sinC = 2根号3 / 3