Question

If cos 0= −1/2 and 9<0<180, find cos (0/2).

a) √2/2
b) √3/2
c) −√3/2
d) −√2/2

Answer 1

To find cos (0/2), divide 0 by 2, which gives 0. Since cos 0 = -1/2, cos (0/2) will also be -1/2.

Step-by-step explanation:

To find cos (0/2), we first need to find the value of cos 0. Given that cos 0 = -1/2 and 9<0<180, we know that 0 lies in the second quadrant. In the second quadrant, cos 0 is negative. Therefore, cos 0 = -1/2.

Now, to find cos (0/2), we divide 0 by 2, which gives us 0. Since cos 0 = -1/2, cos (0/2) will also be -1/2.

Therefore, the correct answer is d) -√2/2.