Question

Which angle is a solution of:

2 sin 2x - 1 = 0
Select the appropriate response:
A) 180°
B) 120°
C) 225°

50 POINTS

Answer 1

C) 225°

Explanation:

2sin²x = 1

sin²x = ½

sinx = +/- 1/sqrt(2)

Basic angle: 45°

In one complete cycle,

45, 180-45, 180+45, 360-45

45°, 135°, 225°, 315°

Answer 2

Answer and Step-by-step explanation:

Let's solve this like a regular equation:

2sin(2x) - 1 = 0

2sin(2x) = 1

sin(2x) = 1/2

Replace 2x with y:

sin(y) = 1/2

What angles for y will make this true? Think to the unit circle; the possible angles are 30° and 150°.

Then, x = 30/2 = 15°or 150/2 = 75°.

(Note that none of the answer choices matches, so the problem/choices may be copied incorrectly)