Чтобы перевести градусы в радианы, умножаем на число π и делим на 180°.
1) 2° =(2°*π)/180° = π/90
2) 10° =(10*π)/180° = π/18
3) 40° =(40°*π)/180° = 2π/9
4) 50° =(50°*π)/180° = 5π/18
5) -135° =-(135°*π)/180° = -3π/4
6) -270° =-(270°*π)/180° = -3π/2
7) 1021° = (1021*π)/180° =1021π/180
8) 905° = (905°*π)/180° = 905π/180