Trigonometry Laws and Identities

Question 1

sin^2(θ) + cos^2(θ)

Answer 1

1

Question 2

tan^2(θ) + 1

Answer 2

sec^2(θ)

Question 3

cot^2(θ) + 1

Answer 3

csc^2(θ)

Question 4

sin(2θ)

Answer 4

2sin(θ)cos(θ)

Question 5

cos(2θ)

Answer 5

cos^2(θ) - sin^2(θ)
2cos^2(θ) - 1
1 - 2sin^2(θ)

Question 6

tan(2θ)

Answer 6

2tan(θ)/ (1-tan^2(θ))

Question 7

Law of Sines

Answer 7

sina/a = sinb/b = sinc/c

Question 8

Law of Cosines

Answer 8

a^2 = b^2 + c^2 -2bc*cos(a)