Задание 3.Расположите числа в порядке возрастания:

№ 4)  cos (-40π/3) = -- 0,5;

№ 1)   cos (30π/4) = 0

№ 3)  cos (9π/4) = 0,707

№ 2)  sin(5π/2) = 1.  

Пошаговое объяснение:

№ 1.

cos (30π/4) = cos (30·180°/4) = cos 1350° = cos (270°+360°·3) = cos 270° = 0

№ 2.

sin(5π/2) = sin (5·180°/2) = sin 450° = sin (90° + 360°) = sin 90° = 1

№ 3.

cos (9π/4) = cos (9·180/4) = cos 405° = cos (45°+360°) = cos (45°+360°) = cos 45° = √2/2 ≈ 1,414 : 2 = 0,707  

№ 4.

cos (-40π/3) = cos (40π/3) = cos (40· 180°/3) = cos (7200°/3) = cos 2400° = cos (240° + 360·6)  = cos 240° = cos (180° + 60°) = - cos 60° = - 1/2 = - 0,5.