Question

已知sin(a-B)=五分之三,sin(a+B)=负五分之三,a-B属于（二分之派,派）a+B属于（二分之三派,派）,则

Answer 1

sin(a-B)=五分之三,a-B属于（二分之派,派）a-B=180-36.87

sin(a+B)=负五分之三,a+B属于（二分之三派,派）,a+B=180+36.87

2B=73.74

cos2B=0.28