Question

计算：cos60°?sin245°+14tan260°+cos30°?sin30°

计算：cos60°?sin245°+14tan260°+cos30°?sin30°．

Answer 1

原式=

1

2

-（

2

2

）²+

1

4

×（

3

）²+

3

2

-

1

2

=

1

2

-

1

2

+

1

4

×3+

3

2

-

1

2

=

3

4

+

3

2

-

1

2

=

1

4

+

3

2

．