It's your turn on the function arctan

Do your best in trying to solve the following problems. In any case some of them are solved in the video and all of them are solved in the pdf file below.

Exercise 1.

Find the values of the following: [1. arctan(-sqrt 3);] [2. arctan(sinpi/2);] [3. sin(arctan 2).]

Exercise 2.

Find the values of the following: [1. arctan(cospi);] [2. cos(arctan 2).]