Question

2sin2

17π

4

+cos

13π

3

tan(-

7π

4

)+cos

3π

2

=______．

Answer 1

2sin2

17π

4

+cos

13π

3

tan(-

7π

4

)+cos

3π

2

=2sin2(4π+

π

4

)-cos (4π+

π

3

)tan(2π-

π

4

)+cos (π+

π

2

)
=2sin²

π

4

+cos

π

3

tan

π

4

-cos

π

2

=1+

1

2

-0=

3

2

．
故答案为：

3

2

．