Given:
Given that a trigonometric statement.
Required:
To check whether the given statements are true or false`.
Step-by-step explanation:
(1)
Now consider LHS side of the given statement,
![\cos(-(5\pi)/(3))=\cos(2\pi-(5\pi)/(3))](https://img.qammunity.org/2023/formulas/mathematics/college/9hr8xf1cv3v3odrcc8j73xa6ewzgx7v80m.png)
Because adding 2π does not change the value of a trigonometric function.
Now,
![\begin{gathered} \cos(2\pi-(5\pi)/(3))=\cos(\pi)/(3) \\ \\ =(1)/(2) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/z49707gy56tijv0c1r7nj46r7qxlesvj5t.png)
Therefore, the statement is false.
(2)
![\begin{gathered} cot(-(11\pi)/(3))=cot(\pi)/(3) \\ \\ =(1)/(√(3)) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/4bnugclmfied3wcyydyui84o89ncmgufgf.png)
Therefore, the statement is False.
(3)
Remove full rotations of 2π until the angle is between 0 and 2π.
![\begin{gathered} \sin((27\pi)/(2))=\sin((3\pi)/(2)) \\ \\ =-1 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/5pm9eh7cx63nhid93fontud0ij39p1rpc1.png)
Therefore, the statement is TRUE.
Final Answer:
The first and second statement are FALSE and the third one is TRUE.
.