Trig Identities
What is the reciprocal of sinX?
cscX
What is the exact value of sin 60
√3/2
Would I use the sin sum or difference formula?
sin(165)= sin(135 +30)
sin sum formula
What types of triangles is Law of Sines used to solve?
AAS and ASA (possibly SSA)
What types of triangles is Law of Cosines used to solve?
SAS or SSS
What is cosX?
secX= 5/8
cosX= 8/5
Using sum and difference formulas for sine, cosine, and tangent.
How do you know when to use a sum vs a difference formula?
When you find two angles that are added together to sum the original angle.
How do you set up an equation using Law of Sines?
sinA/a=sinB/b=sinC/c
a/sinA=b/sinB=c/sinC
How do you set up Law of Cosines?
a2=b2+c2-2bc(cosA)
b2=a2+c2-2ac(cosB)
c2=a2+b2-2ab(cosC)
Given sinX= 3/5
Find cosX
cosX= 4/5
Find the exact value of sin 15
(√6-√2)/4
What is the first step in trying to solve sin(a + b) given cos a= 4/5 and sin b= -15/17
Use the Pythagorean identity sin2x + cos2=1 to solve for cos b and sin a
What information is needed to use Law of Sines?
An angle and it's corresponding side.
Solve for side b. Round to the nearest tenth.
B= 24 c=22 a=19
b=9
Given sinX= -√7/4
cosX= -3/4
Find tanX
√7/3
Find the exact value of sin 75
(√2 + √6)/4
What formula is the following?
cos(a)cos(b) + sin(a)sin(b)
cosine difference formula
Solve for angle B. Round to the nearest tenth.
a=25 b=16 A=82
36.9 degrees
A=37 b=8 c=11
a= 6.7
tanX= √15/3
cosX= √10/4
Find sinX
sinX= 5√6/12
Find the exact value of cos 105
(-√6- √2)/4
What is cos(a-b)
cos(a)= 4/5 cos(b)= 8/17
sin(a)= 3/5 sin(b)= -15/17
-13/85
solve for side a.
B= 120 C=21.8 c=3 b=7
a= 5
Find angle C. Round to the nearest tenth.
a=20 b=30 c=40
Angle C= 104.5 degrees