Trig Formulas

Question 1

What Pythagorean identity equals one?

Answer 1

cos²σ + sin²σ

Question 2

Pythagorean identity that equals sec²u

Answer 2

1 + tan²σ

Question 3

Pythagorean identity that equals csc²σ

Answer 3

1 + cot²σ

Question 4

Double angle formula involving sin

Answer 4

sin2σ = 2sinσcosσ

Question 5

Double angle formula involving cosine

Answer 5

cos2σ = cos²σ - sin²σ

= 2cos²σ - 1

= 1 - 2sin²σ

Question 6

Double angle formula involving tangent

Answer 6

2tan σ

1 - tan²σ

Question 7

What is the reciprocal of sinσ

Answer 7

1

csc σ

Question 8

What is the reciprocal of cos σ

Answer 8

1

sec σ

Question 9

What is the reciprocal of tan σ

Answer 9

1

cot σ

Question 10

What is the reciprocal of csc σ

Answer 10

1

sin σ

Question 11

What is the reciprocal sec σ

Answer 11

1

cos σ

Question 12

What is the reciprocal of cot σ

Answer 12

1

tan σ

Question 13

What is the sum of the sin(σ+Ø)

Answer 13

sinσcosØ+cosσsinØ

Question 14

What is the cos(σ + ß)

Answer 14

cosσcosß + sinσsinß

Question 15

What is the sum of tan(σ + ß)

Answer 15

tanσ + tanß

1 - tanσtanß

Question 16

What is the half angle formula

sin σ/2

Answer 16

Question 17

What is the formula for proj_vu

Answer 17

Question 18

What is the formula to find an angle between vectors

Answer 18

Question 19

What is the formula we use to get amplitude and period

Answer 19

y=d + a sin(bx-c)

Question 20

How do you calculate the period

Answer 20

2π

b

Question 21

What formula finds a vector in the same direction

Answer 21

Question 22

What is the formula for DeMoivre’s Theorum

Answer 22

z = r(cos σ + i sin σ)

= zⁿ = [r(cos σ + i sin σ)]ⁿ

= rⁿ(cos nσ + i sin nσ)

Question 23

What formula finds the nth root of a complex number

Answer 23