17.4 CHAPTER 17. TRIGONOMETRY
0
1
− 1
90 ◦◦ 180 270 ◦◦ 360
1 st 2 nd 3 rd 4 th
+V E +V E−V E−V E
0 ◦/ 360 ◦
90 ◦
180 ◦
270 ◦
2 nd
+VE
−VE
3 rd
−VE
4 th
1 st
+VE
Figure 17.11: The graphand unit circle showingthe sign of the sine function.
0
1
− 1
90 180 270 360
0
2
4
6
8
− 2
− 4
− 6
− 8
◦◦◦ ◦◦90 180 270◦◦◦ 360
1 st 2 nd 3 rd 4 th
+V E−V E−V E +V E
1 st 2 nd 3 rd 4 th
+V E−V E +V E−V E
Figure 17.12: Graphs showing the sign of the cosine and tangent functions.
1 st 2 nd 3 rd 4 th
sin +V E +V E −V E −V E
cos +V E −V E −V E +V E
tan +V E −V E +V E −V E
Table 17.7: The signs ofthe three basic trigonometric functions in each quadrant.
