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!
Answer:
The first 2
Step-by-step explanation:
First expression = -4+30-3 =23
Second expression = 8(10+4)= 112.
The others would lead to a negative number.
Remember negative times negative = positive
Negative times negative times negative = negative
I think it's D but I'm not %100 sure