Trigonometry

Question 1

What are the double angle formulas?

Answer 1

sin2A = 2sinAcosA
cos2A = cos^2A-sin^2A
tan2A = 2tanA/1-tan^2A

can get here by using addition formulas and replacing ‘B’ with ‘A’

Question 2

What are the basic trig identities?

Answer 2

tan = sin/cos
sin^2+cos^2=1

Question 3

What is the sine rule?

Answer 3

sinA/A = sinB/B

Question 4

What is the cosine rule?

Answer 4

a^2 = b^2 + c^2 - 2bc(cosA)

or
cosA= b^2 + c^2 - a^2 /2bc

Question 5

How do you convert from radians to degrees and vice versa?

Answer 5

Radians to degrees:
divide by pie and x180

Degrees to radians:
divide by 180 and multiply by pie

Question 6

What is formula for arc length using radians?

Answer 6

rx:
angle x radius

Question 7

What is the formula for sector area using radians>

Answer 7

1/2 x radius squared x angle

Question 8

What are the reciprocal trig functions?

Answer 8

sec^2x = 1 + tan^2x
cosec^2x = 1 + cot^2x

Question 9

What is formula for mutually exclusive?

Answer 9

P(A or B) = P(A) + P(B)

Question 10

What is formula for non-mutually exclusive events?

Answer 10

P(A or B) = P(A) + P(B) - P(AnB)

Question 11

How to derive sec identity?

Answer 11

divide cos^2x + sin^2x = 1 by cos^2x

Question 12

How to derive cosec identity?

Answer 12

divide cos^2x + sin^2x = 1 by sin^2x

Question 13

What is the R addition formula?

Answer 13

asin0 + bcos0 = Rsin(0+a)
acos0+bsin0 = Rcos(0-a)