0 Đ⇔ = +Π0,5 Đ2 2X X K = − + =X K3⇔ = ⇔ =Π ΠX K X K2 3 =2= + +2 22 SIN 3SIN COS 5 COSY X X X X= − + + +1 COS 2X X X1 COS 2 3 SIN 2 5

3,0 đ

⇔ = +

π

0,5 đ

2 2x x k = − + =x k3⇔ = ⇔ =

π π

x k x k2 3 =2

= + +

2

2

2 sin 3sin cos 5 cos

y x x x x

= − + + +

1 cos 2

x x x

1 cos 2 3 sin 2 5.

( ) ( )

2 2

3 3 7

cos 2 sin 2

x x

2 2 2

b)