π |
2 |
∴0<cost<1,
f(t)=
1 |
cost |
a |
1?cost |
1 |
cost |
a |
1?cost |
acost |
1?cost |
1?cost |
cost |
a |
當(dāng)且僅當(dāng)
acost |
1?cost |
1?cost |
cost |
求得
a |
∴a=9,
故答案為:9.
π |
2 |
1 |
cost |
a |
1?cost |
π |
2 |
1 |
cost |
a |
1?cost |
1 |
cost |
a |
1?cost |
acost |
1?cost |
1?cost |
cost |
a |
acost |
1?cost |
1?cost |
cost |
a |