Ask Me Help Desk - sin (-105°) Find the exact value of this expression.

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sin (-105°) Find the exact value of this expression.

Find the exact value of this expression:

sin (-105°)

I've found multiple solutions online for sin (105°) but not sin (-105°), please help.
Please show work if possible. I'm getting right numbers but my positive / negative symbols are off and I don't know why.

You should know that $\sin(x) = - \sin(-x)$ .

Don't quote me, but this might work...

$Sin(-105) = ?$
$105 = 60 + 45$
$0 - 105 = -105$
you could use
$Sin(0-105) = Sin(0)Cos(105) - Sin(105)Cos(0)$
and since sin(0)=0 and cos(0)=1
$= -Sin(105)$
$-(sin(60 + 45)) = -(Sin(60)Cos(45) + Sin(45)Cos(60))$

Does this Help?

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