<em><u>Answer:</u></em>
where "n" is an integer that belongs to Z.
<em><u>Explanation:</u></em>
<u>The equation given is:</u>
2cos²(x) - 5cos(x) + 2 = 0
To factor this equation, we will use the quadratic formula shown in the attached image.
<u>From the given equation:</u>
a = 2
b = -5
c = 2
<u>This means that:</u>
either cos(x) = .......> This solution is rejected as the value of the cosine function lies between -1 and 1 only.
or cos(x) = ......> This solution is accepted as it lies within -1 and 1
<u>Now, using the inverse of the cosine, we can find that:</u>
where "n" is an integer that belongs to Z.
Hope this helps :)