Question

问几道数学题~高二的正弦定理要答案和步骤明确点~必修五四页练习1,2

Answer 1

(1) a/sinA=c/sinC a=c*sinA/sinC=102^(1/2)cm;

(2) a/sinA=c/sinC a/sinA=c/sin(180-A-B)

sin(180-60-45)=sin(60+45)=sin(60)*sin(45)+cos(60)*cos(45)

a=40*3^(1/2)/2^(1/2)(3^（1/2)+1)