formulas chapter 6

Question 1

Law of sin

Answer 1

a/sinA = b/sinB = c/sinC

Question 2

Law of cos a^2 =

Answer 2

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

Question 3

law of cos b^2

Answer 3

b^2= a^2+c^2-2ac cosB

Question 4

law of cos c^2

Answer 4

c^2 = a^2+b^2-2ab cosC

Question 5

Law of cos: cos A

Answer 5

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

Question 6

Law of cos: cos B

Answer 6

cos B= (a^2 + c^2 - b^2) / 2ac

Question 7

Law of cos: cos C

Answer 7

cos C= (a^2 + b^2 - c^2) / 2ab

Question 8

how to tell if vectors are othogonal

Answer 8

if u dotted with v equals zero

Question 9

how to find angle between two vectors if θ is the angle between two nonzero vectors u and v

Answer 9

θ= u · v / |v||u|

Question 10

herons formula
Area =
s=

Answer 10

area= √s(s-a)(s-b)(s-c)
s = 1/2 (a+b+c)

Question 11

dot product formula

Answer 11

u · v = u₁v₁+u₂v₂

Question 12

comlex numbers stuff

Answer 12

z= a-bi
r= √a² +b²
tan θ= b/a

Question 13

formula to find a vector with the given magnitude and same directuon as u

Answer 13

|v|= |v| times u / |u|

Question 14

magnitude formula

Answer 14

√(x₂-x₁) ²+ (y₂-y₁)²

Question 15

direction θ

Answer 15

θ= tan⁻¹ (ʸ⁄ₓ)