is in quadrant I, so
.
is in quadrant II, so
.
Recall that for any angle
,

Then with the conditions determined above, we get

and

Now recall the compound angle formulas:




as well as the definition of tangent:

Then
1. 
2. 
3. 
4. 
5. 
6. 
7. A bit more work required here. Recall the half-angle identities:



Because
is in quadrant II, we know that
is in quadrant I. Specifically, we know
, so
. In this quadrant, we have
, so

8. 
Answer:
B
Step-by-step explanation:
cause it's got a 5.....5 x 5 = 25.......make sense
Answer:
Looks like -6
Step-by-step explanation:
At every 1.0 unit, boiling point decreases 1.8 unit, which means the slope m = -1.8.