Question

Given: cos(3x – Pi) = Negative StartFraction StartRoot 3 EndRoot Over 2 EndFraction, where 0 ≤ x < 180° Which values represent the solutions to the equation? {10°, 110°, 130°} {20°, 100°, 140°} {30°, 330°, 390°} {60°, 300°, 420°}

Answer 1

Answer:

Step-by-step explanation:

Given the expression cos(3x-π) = -√3/2, we are to find the values of x that represent the solutions to the equation.

cos(3x-π) = -√3/2

take inverse cos of both sides

cos⁻¹[cos(3x-π)] = cos⁻¹[-√3/2]

3x-π = cos⁻¹[-√3/2]

3x-π = -30°

since 180° = π rad

Hence;

3x- 180° = -30°

3x =  -30°+ 180°

3x = 150°

x = 150°/3

x = 50°

Since cos is negative in the first second and 3rd quadrant;

3x-180° = -30°

In the second quadrant;

3x-180° = 180-30

3x - 180 = 150

3x = 150+180

3x = 330

x = 110°

In the third quadrant;

3x-180° = 270+30

3x - 180 = 300

3x = 300+180

3x = 480

x = 480/3

x = 160