A.5 – Trig with Calculators, Coterminal Angles
When using a calculator for this entire year, always approximate to 4 decimal places
(even if the directions tell you otherwise).
cos 37.8°
sin 58.75 °
sec 78°
csc
Trig with Calculators
Find ϴ between 0° and 90°.
tan
3.152
sin
0.3733
sec
1.0768
cot
0.0975
Trig with Calculators
Find angles in quadrants II, III and IV using the reference angle from quadrant I.
Trig with Calculators
Find θ if sin θ = -0.5592 and θ terminates in QIII with 0o < θ < 360o.
Find θ if tan θ = -0.8541 and θ terminates in QIV with 0o < θ < 360o.
Find θ if sin θ = 0.9743 and θ terminates in QII with 0o < θ < 360o.
Trig with Calculators
NOTE:
Use exact values to simplify:
60°
60°
60°
Coterminal Angles
Two angles in standard position with the same terminal side are called coterminal.
Example: 45°, -315° and 405° are coterminal.
How to find the smallest positive coterminal angle:
If
! 360°, subtract 360° repeatedly.
If
" 0°, add 360° repeatedly.
Coterminal Angles
Find the angles with the smallest possible positive measure that is coterminal.
810°
#
$
-520°
#
%
Coterminal Angles
Are the following coterminal?
α = 20°, β = −380°
State all the coterminal angles of 10°.
A.5 – Homework
Pg. 742 #1 – 29 odd, 57 – 65 odd, 75 – 81 odd