Help me with my algebra 2 ?

Question

find the exact value of sin165

a root6 - root2 /4

b root6 + root2 /4

c root2 - root6 /4

d root6 - root2 /4

Answer 1

sin165

=sin(90+75)

=sin90cos75+cos90sin75

=cos75

=cos(30+45)

=cos30cos45-sin30sin45

=sqrt(3)/2. sqrt(2)/2 - 1/2. sqrt(2)/2

=[sqrt(6)-sqrt(2)] /4

Answer:

a (root6 - root2) /4

d (root6 - root2 )/4

N.B. According your choices no answer.

Use paranthesis where necessary.

Be more careful

Answer 2

sin165 =sin(90+75) =sin90cos75+cos90sin75 =cos75 =cos(30+45) =cos30cos45-sin30sin45 =sqrt(3)/2. sqrt(2)/2 - 1/2. sqrt(2)/2 =[sqrt(6)-sqrt(2)] /4 Answer: a (root6 - root2) /4 d (root6 - root2 )/4

answer is not included in the choices