Question

sin165 (find exact value by using sum or difference identity)

Answer 1

hint : 165 = 210-45

Answer 2

haha good point

Answer 3

once you get that what do you do after that?

Answer 4

use the formula :
sin(a-b) = sincosb - cosasinb

Answer 5

right! :)

Answer 6

I have another one..

Answer 7

tan285

Answer 8

285=240+45
use the formula:
tan(a+b) = (tana + tanb)/(1-tanatanb)

Answer 9

can you get then answer while i get it so I can make sure it is right

Answer 10

hmmmm... u first
use, tan240=sqrt(3), tan45=1
tell m what u get after that

Answer 11

I got sqrt(3)+1 over 1-sqrt(3)

Answer 12

yes, correct
actually, u need rationalize of it right ? simplify it

Answer 13

it would equal to one right

Answer 14

a fraction would be 1 if numerator and denominator was same

Answer 15

oh when rationalized i got -2

Answer 16

multiply by conyugate of denominator that fraction

Answer 17

NM

Answer 18

it means