1. Determining signs of Trig Functions (Pos/Neg)
Last class we found trig values using an x-y coordinate. Not all trig values are positive
x-
x+
y+ y
y+
We can determine the signs of trig values based on the quadrant that the terminal side of the angle falls in x
x-
x+
The signs of the x and y coordinates factor into the signs of the trig values
y-
y-

2. Finding Trig Values from an x-y coordinate
Find the 6 trig functions for an angle which has terminal side passing through (-3, 4) and give them the proper signs y
This comes from the y coordinate which is positive x

3. Finding Trig Values from an x-y coordinate
Find the 6 trig functions for an angle which has terminal side passing through (-3, 4) and give them the proper signs y
The hypotenuse is always positive
So we have positive over positive meaning the sine is positive in the 2nd quadrant x

4. Finding Trig Values from an x-y coordinate
Find the 6 trig functions for an angle which has terminal side passing through (-3, 4) and give them the proper signs y
This is comes from the x-coordinate which is negative x

5. Finding Trig Values from an x-y coordinate
Find the 6 trig functions for an angle which has terminal side passing through (-3, 4) and give them the proper signs y
Hypotenuse – always positive
Negative over positive making cosine negative in the 2nd quadrant x

6. Finding Trig Values from an x-y coordinate
Find the 6 trig functions for an angle which has terminal side passing through (-3, 4) and give them the proper signs y
y-coordinate - positive
x-coordinate - negative x
positive over negative means tan is negative in the 2nd quadrant

7. Finding Trig Values from an x-y coordinate
Find the 6 trig functions for an angle which has terminal side passing through (-3, 4) and give them the proper signs y
csc has the same sign as sin, sec is the same as cos, cot is the same as tan x

8. Determining signs of Trig Functions (Pos/Neg)
Add this into the original chart we started with y
sin+
x-
sin+
x+
cos+
cos-
y+
y+
tan+
tan-
csc+
csc+
sec+
sec-
cot+
cot- x
x-
sin-
x+
sin-
cos-
cos+
y-
y-
tan+
tan-
csc-
csc-
sec-
sec+
cot+
cot-

9. Finding Trig Values from an x-y coordinate
Find the 6 trig functions for an angle which has terminal side passing through (2, -7) and give them the proper signs y x

10. Finding Trig Values from an x-y coordinate
Find the 6 trig functions for an angle which has terminal side passing through (-5, 3) and give them the proper signs y x

11. Homework – pg 697 #9, 13, 14, 17, 20