7­4.notebook
November 18, 2010
7­4 Evaluating and graphing sin θ and cos θ
Reference angles ­ always acute with x­axis.
quadrant I : use as is
quadrant II and III : use 1800
quadrant IV : use 3600
Mar 10­10:45 AM
Exs. sin 1500
sin 2400
cos 3300
cos 2250
Mar 10­10:48 AM
1
7­4.notebook
November 18, 2010
Evaluate with a calculator to 4 decimal places.
sin 1780
cos 1780
sin (­500)
cos ­3.4
h.w. p.278 1­9
Mar 10­10:51 AM
Evaluating sin θ and cos θ using tables.
00
300
450
600
900
sin θ
0
1/2
√2/2
√3/2
1
cos θ
1
√3/2
√2/2
1/2
0
.
(0,1)
.
.
(­1,0)
(1,0)
.
(0,­1)
Mar 10­10:53 AM
2
7­4.notebook
November 18, 2010
S
A
students
all
T
C
take
calculus
Mar 10­12:01 PM
Evaluate the following:
sin 1500
cos 1500
sin π
cos π
sin 7π/6
cos 7π/6
sin ­300
Mar 10­12:03 PM
3
7­4.notebook
November 18, 2010
h.w. p. 279 10­14
h.w. p. 280 11­18
Mar 10­12:06 PM
4