(a)
\The trigonometric function is ,
.
Since lies in quadrant I,
is also lies in quadrant I.
(b)
\Find .
Using half - angle formulas: .
Substitute in above formula.
(Since angle
is in quadrant I)
Find .
Using half - angle formulas: .
Substitute in above formula.
(Since angle
is in quadrant I)
Find .
Using half - angle formulas: .
From Pythagorean theorem, .
Substitute and
in above formula.
.
(a) lies in quadrant I.
(b) ,
and
.