By using The half-angle formula
cos X/2 = ±√[(1 + cos X)/ 2]
But we have cos x=2/3
= ±√[(1 + 2/3)/ 2]
= ±√[(5/3 )/ 2]
= ±√[(5/5]
=±√1
Therefore answer is ±1
cos A/2 = ±√[(1 + cos A )/ 2]
Answer:
No.
Step-by-step explanation:
Sam is incorrect because if you look at the original problem, you'll see that he has missed the negative sign!
90 / 9 does equal 10, but 90 / -9 equals -10.
The only way to get a positive answer is if both the divisor and dividend are positive or if they are both negative.
Thus, the correct answer should be -10.
