Rewrite cos 52 degree in terms of its cofunction cos 52 degr
     Rewrite cos 52 degree in terms of its cofunction.  cos 52 degree =  degree  (Type an exact answer. Simplify your answer. Type an   
  
  Solution
The value of a trig function of an angle equals the value of the cofunction of the complement of the angle.
Since co-function of cosx :
cosx = sin(90 -x)
So, cos52 = sin(90 -52)
= sin38

