TRIGONOMETRIC FUNCTIONS - EXERCISE 2 TRIGONOMETRIC FUNCTIONS - EXERCISE 2 
(give an exact answer).
and 
, find 
(give an exact answer).
Solution:
(a) Observe that 
5 whole revolutions 
. Since 
has period 
,
it follows that
. The angle 
lies in the third quadrant and has 
as reference angle,
therefore 
is a point on the angle and on the unit
circle, from which we obtain:
(b) Observe that
, from
which we obtain that 
.
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Luis Valdez-Sanchez