Answer:
13
Step-by-step explanation:
The closest multiple of 6 less than 80 is 13.
13×6=78
How many are left over?
80 - 78 = 2
remains, and this can be simplified to
13
Hope this helps!! (I know it sounds a little complicated but it's easy to understand it with practice :)
Answer: sin = ±
Step-by-step explanation:
We very well know that,
cos2A=1−2sin²A
⟹ sinA = ±
As required, set A = & cos a=
,thus we get
sin =±
∴ sin =±
= ±
since ,360° < <450°
,180° < <225°
Now, we are to select the value with the correct sign. It's is obvious from the above constraints that the angle a/2 lies in the III-quadrant where 'sine' has negative value, thus the required value is negative.
hope it helped!