cosA |
cosB |
sinB |
sinA |
∴2A=2B或2A+2B=π,即A=B或A+B=
π |
2 |
当A=B时,有sin(π-2A)=cosA,即sinA=
1 |
2 |
π |
6 |
2π |
3 |
当A+B=
π |
2 |
π |
2 |
∴A=B=
π |
6 |
2π |
3 |
(Ⅱ)由(Ⅰ)及题设知:f(x)=sin(2x+
π |
6 |
π |
3 |
π |
6 |
当2x+
π |
6 |
π |
2 |
π |
2 |
π |
6 |
即f(x)=2sin(2x+
π |
6 |
π |
3 |
π |
6 |
它的相邻两对称轴间的距离为
π |
2 |
cosA |
cosB |
b |
a |
C |
2 |
cosA |
cosB |
sinB |
sinA |
π |
2 |
1 |
2 |
π |
6 |
2π |
3 |
π |
2 |
π |
2 |
π |
6 |
2π |
3 |
π |
6 |
π |
3 |
π |
6 |
π |
6 |
π |
2 |
π |
2 |
π |
6 |
π |
6 |
π |
3 |
π |
6 |
π |
2 |