PHỬỤNG TRỠNH COSX = COSΑA/ COS X  COS   X    K 2 (  K Z  )...

2. Phửụng trỡnh cosx = cosα

a/ cos x  cos   x    k 2 (  k Z  )

cos . : 1 1.

x a  x  a k   k Z

cos x a ẹieàu kieọn arccos a 2 ( )

     

b/



     

u v u  2 v 

c/ cos u  cos v  cos u  cos(   v ) d/ cos sin cos cos

 

     

e/ cos sin cos cos

Caực trửụứng hụùp ủaởc bieọt:

cos 0 ( )

 cos x  1  x k  2 (  k Z  )

x   x   2  k k Z 

cos x  1  x    k 2 (  k Z  )

2

2

cos x   1 cos x   1 sin x   0 sin x  0  x k   ( k Z  )