Question

Precal @Vocaloid

Answer 1

Calculate the exact value of sin(105) two different ways, once using a sum or difference identity and once using a half angle identity.

Missed these lessons cause AP exams so I don't know much, lol.

Answer 2

for the sum/difference identity the goal is to re-write 105degrees as a sum or difference of two other numbers that can be easily found on the UC

so sin(105) = sin(150-45) = > then use the sin difference formula to plug in the appropriate values from the UC

Answer 3

Mhm

Answer 4

same thing for sin half identity, if sin(alpha/2) = sin(105) then alpha = 210, plug into the formula

Answer 5

Nice, just going to keep this open for my homework. These identities will be fun to memorize xD

Answer 6

I have a trick for remembering Sum and Difference identities

Answer 7

Do share

Answer 8

I don't have my notes LOL
I'll tell you later.

Answer 9

Okay

Answer 10

Never mind. So remember, sine identities are the same signs.
Meaning, sin(A+B)=sinAcosA+sinBcosB
Same addition signs