Trigonometry

formulas

100

How to find sine, cosine, and tangent

sin=opp/hyp

cos=adj/hyp

tan=opp/adj

200

how to find central angles

add and subtract 360

300

how to convert from radians to degrees

180/π

400

Sum Formula for Sine

sin(α+β)= sinα cosβ + cosα sinβ
 

500

sine double angle formula 

sin2a= 2sina cosa

conversions

100

120° convert to radians 

2/3π

200

3π/10 convert to degrees

54°

300

395° convert to radians 

79π/36

400

1.88 convert to degrees

107.7°

500

π° convert to radians 

π²/180

solve

100

find cos (300°)

1/2

200

find sin(45 + 30)

√6+√2/4

300

tan= 2 ; find cos and sin

cos = 0.4

sine = 0.8

400

cos (8π/3)

-√3/2

500

sin=0.840 ; find cos and tan

cos= 0.542

tan= 1.54

solve

100

sinx=1/2

x= 30+360k

x=150+360k

200

cos-1(1/2)

x= 60+360k

x=-60+360k

300

tanx=15

x=86.2+180k

400

4sin²x-1=0

sinx= 1/2 ; x=30+360k or x=150+360k

sinx=-1/2 ; x=-30+360k or 210+360k

500

tanx²-1=0

x=45+180k

x=-45+180k

solve

100

2cos²x-1=0

cos^-1=(√2/2);45+360k or -45+360k

cos^-1=(-√2/2);135+360k or -135+360k

200

tan²x-3=0

tan^-1√3; x=60+180k

tan^-1(-√3); x=-60+180k

300

cos(3x-100)=-1/√2

x=235/3+120k

x=35/3+120k

400

sin(4x-70)=-√3/2

x=10/4+90k 

x=310/4+90k

500

tan(2x-110)=14

x=97.95+90k