Question

Which of the following is a solution to 2cos2 x – 2 = 0?

Answer 1

To simplify:
2 cos 2x - 2 = 0
2 cos 2x = 2
cos 2x = 1 --- (1)

To find the principal angle, do cosh 1 (cos^-1 1)
Based on 1, as the value of cos is positive, find all the angles for this expression by doing the ASTC method (A and C only)

A = principal angle + 2(pi)(n), where n is 0,1,2, or any other integer more than 0
C = 2pi - principal angle + 2(pi)(n), where n is 0,1,2, or any other integer more than 0

Answer 2

is it 180 deegrees?

Answer 3

@dauspex
A-0
B-30
C-180
D-330

Answer 4

0=2cos(2x)–2
multiply both sides by (-1/4)
0=[1-cos(2x)]/2=sin^2(x)

0=sinx

Every possible x that gives you 0 is 180n where n is any integer, so for instance for n=0, the answer is 0. For n=1, you have 180. There are literally infinite answers, but only A and C are right here.

Answer 5

0 or 180