Solve each of the following equations for 0° ≤ θ < 360°

I don't know to do this, I only have a few days pleas help.
Solve each of the following equations for 0° ≤ θ < 360°.

1.) 2 cos θ = 1


2.) (tan θ + 1) (sec θ – 1/2) = 0

3.) sin2 θ + 3 sin θ + 2 = 0

4.) sin θ/cos θ = tan2 θ

5.) 4 sin θ cos θ = 1

i'll do the last one

remember 2sin(x)cos(x) = sin(2x)?
4sin(x)cos(x) = 1
2 * [ 2sin(x)cos(x) ] = 1
2 * [ sin(2x) ] = 1
sin(2x) = (1/2)
(2x) = arcsin(1/2)
(2x) = 30deg
x = 15

remember sin on 1st & 2nd quadrant is same positive?
x = 15 <== ans
x = 15 + 90 = 105 deg <== ans

I will answer question 1 only to show you how it is done.

Question 1:

Let x denote theta:

cos(x) = 1/2.
Since cosine is positive in the first and fourth quadrants, x is either 60 degrees or 300 degrees.
This is because it is your 1, sqrt(3), 2 triangle and when the adjacent side is 1 and the hypotenuse 2 the respective angle is 60 degrees.

I hope you listened to your teacher in Grade 8!!!