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2.1 Trigonometry Functions of Acute Angles
For any acute angle A:
Sin A =
csc A =
Cos A=
sec A=
Tan A =
cot A=
Which side is opp? Adj? Hyp? < C = 90 in all rt triangles.
Find the 6 trig functions of < A
Find the 6 trig functions of <B
Cofunctions: compliments <A +<B =90
Cofunction Identities: for any acute angle A:
Sin A= cos (90-A) and
cos A = sin(90-A)
CscA = sec (90-A) and
sec A = csc(90-A)
Tan A= cot (90-A)
cot A = tan(90-A)
Cos 52= _______
Find A : cos(A+4)=sin(3A+2)
QI: 0<<90
Is sin 13> sin 33 ?
Tan 71 =
as  goes from 0 to 90 and r is fixed:
Sin  =
increases- y leg gets bigger
Cos =
decreases- x gets smaller
Tan =
increases- y gets bigger, x small
is cos 24 > cos 10 ?
Special Triangles – Exact values!
30-60-90
1 3 2
45-45-90
1 1 2
sin 30 =
cos 60=
tan60=
chart:
sin
cos
0
30
45
60
90
Approximate Values: calc:
Pg 68 1-9 all, 11-14 all
17-29odd, 43-46 all
2.2 Trig Functions of non acute angles
Reference Angles: the positive acute angle formed by the terminal side of an
angle and the x axis.
1. 218
2. 1387
30 - 60 - 90
1 3 2
45 – 45- 90 triangles
1 1 2
Find the exact values of the six trig functions for 210.
Find the exact values of the 6 trig functions for –240.
Find the exact value of:
1. csc –45
2. tan 330
3. sec 315
Find the value of : cos 120 + 2sin2 60 – tan2 30
Pg 75 1-33 odd,51,53
2.3 Using a Calculator:
Approximations!!! The calc rounds answers.
Sin 32
cos 42 20
tan –377
What if we need the angle measure?
Sin A= .3
cos A= -.7
secA = 4
csc32
sec 42 20
cot B = 5.6
Pg 80 5-23,
29-35 odd