\
The functions are and
.
Find .
Apply sum formula : .
.
\
Find the value of :
From figure (1):
\The circle equation is and point is
.
Rewrite the equation:.
It is in the form of .
Then .
Substitute the point in a circle equation.
.
Observe figure(1) :
\ lies in first quadrant.
.
Substitute and
.
.
.
Substitute and
.
.
.
.
\
Find the value of :
From figure (2):
\The circle is and point is
.
Rewrite the equation: .
It is in the form of .
Then .
Substitute the point in a circle equation.
Observe figure(1) :
\The point lies in quadrant IV, then .
.
.
As lies in quadrant IV.
.
.
.
.
\
Consider
Substitute and
in
.
.
.
\
.