Exam 2

Question 1

Pythagorean Identities (Trigonometric Identities)

Answer 1

Sin2x+cos2x=1
Cot2x+1 = csc2x
tan2x+1 = sec2x

Question 2

Reciprocal Identities (Trigonometric Identities)

Answer 2

cscx=1/sinx
secx=1/cosx
cotx=1/tanx

Question 3

Quotient Identities (Trigonometric Identities)

Answer 3

Tanx = sinx/cosx
Cotx = cosx/sinx

Question 4

Sum and difference formulas

Answer 4

sin(a+-b) = sinacosb+-cosasinb
cos(a+-b) = cosacosb-+sinasinb

Question 5

Double angle formulas

Answer 5

sin(2x) = 2sinxcosx
cos(2x) = cos2x-sin2x
tan (2x) = 2tanx/1-tan2x

Question 6

Right triangle equations:

Answer 6

sinx = co/h
cosx = ca/h
tan x = co/ca

Question 7

Law of Sines

Answer 7

sin A/a = sinB/b = sinC/c

Question 8

Law of Cosines

Answer 8

a2 = b2 + c2 - 2bccosA
CosA = b2 + c2 -a2/2bc
(then rearrange)

Question 9

Area of triangle

Answer 9

A = 1/2 absinC 
A = 1/2 (a+b+c)
sqrt S (S-a)(S-b)(S-c)