Trigonometria FORMULAK

Question 1

Kosinuaren teorema (a)

Answer 1

a² = b² + c² - 2bc · cos A

Question 2

Kosinuaren teorema (b)

Answer 2

b² = a² + c² - 2ac · cos B

Question 3

Kosinuaren teorema (c)

Answer 3

c² = a² + b² - 2ab · cos C

Question 4

Angeluen batura (sin)

Answer 4

sin (α+β) = sinα · cosβ + cosα · sinβ

Question 5

Angeluen batura (cos)

Answer 5

cos (α+β) = cosα · cosβ - sinα · sinβ

Question 6

Angeluen batura (tg)

Answer 6

tg (α+β) = (tgα + tgβ) / (1 - tgα · tgβ)

Question 7

Angeluen kendura (sin)

Answer 7

sin (α-β) = sinα · cosβ - cosα · sinβ

Question 8

Angeluen kendura (cos)

Answer 8

cos (α-β) = cosα · cosβ + sinα · sinβ

Question 9

Angeluen kendura (tg)

Answer 9

tg (α-β) = (tgα - tgβ) / (1 + tgα · tgβ)

Question 10

Angelu bikoitza (sin)

Answer 10

sin 2α = 2 sinα · cosα

Question 11

Angelu bikoitza (cos)

Answer 11

cos 2α = cos² α - sin² α

Question 12

Angelu bikoitza (tg)

Answer 12

tg 2α = (2 tgα) / (1-tan² α)

Question 13

Angelu erdia (sin)

Answer 13

sin (α/2) = +- [erro (1 - cosα) / 2]

Question 14

Angelu erdia (cos)

Answer 14

cos (α/2) = +- [erro (1 + cosα) / 2]

Question 15

Angelu erdia (tg)

Answer 15

tg (α/2) = +- [erro (1 - cosα) / (1 + cosα)}