Question

已知sin(A)和sin(B)的值,如何求出sin((A+B)/2)的值,谢谢.

Answer 1

sinA=2sin(A/2)cos(A/2),再有(sin(A/2))^2+(cos(A/2))^2=1,可得sinA/2和cosA/2的值,同样求出sinB/2和cosB/2的值

sin((A+B)/2)=(sinA/2)*(cosB/2)+sin(B/2)*(cosA/2)