m |
n |
x |
2 |
x |
2 |
所以y=f(x)的值域为[-1,1];
(2)由已知得A为锐角,f(A)=sinA=
3 |
5 |
则cosA=
1-(
|
4 |
5 |
3 |
5 |
4 |
5 |
24 |
25 |
cos2A=1-2sin2A=1-2×(
3 |
5 |
7 |
25 |
所以f(2A-
π |
3 |
π |
3 |
π |
3 |
π |
3 |
24 |
25 |
1 |
2 |
7 |
25 |
| ||
2 |
24-7
| ||
50 |
m |
x |
2 |
n |
x |
2 |
m |
n |
3 |
5 |
π |
3 |
m |
n |
x |
2 |
x |
2 |
3 |
5 |
1-(
|
4 |
5 |
3 |
5 |
4 |
5 |
24 |
25 |
3 |
5 |
7 |
25 |
π |
3 |
π |
3 |
π |
3 |
π |
3 |
24 |
25 |
1 |
2 |
7 |
25 |
| ||
2 |
24-7
| ||
50 |