So the answer is -5π/3.

14, the numerator and denominator are divided by cosa at the same time, and it is easy to get the answer -3/ 13.

15, s norm = 1/2 ar? = 1/2×π/3×4=2π/3

16. It is easy to draw an image and get the result: {x | π/3+kπ≤ x < π/2+kπ, k ∈ z}

17 solution:

The original formula = cos (π+π/6)+sin (2π+π/3)+tan (-π-π/4)-sin (-π/3-4π).

=(-√3/2)+√3/2+(- 1)-(-√3/2)

= √3/2 - 1

Study hard in the future and do your homework in advance. Don't wait to hand it in before you know it's urgent. Come on, you can make it.