Question

If cos A = 1/2 then the value is cos 3A
Is

Answer 1

Answer:

cos3A=0

Step-by-step explanation:

Here cosA = 1/2

and in the table cos60=1/2

that means A=60

cos3A= cos180

Now, we can write cos180 as cos(90-(-90))

then it will convert into sin(-90) which is equal to 0.

Answer 2

-1

Step-by-step explanation:

use cos(3A) identity=4cos^3(A)-3cos(A)