4cos^2(4x)-3=0

Question

The value π/12 is a solution to 4cos^2(4x)-3=0.

 

a) true

b) false 

 

???

 

Do I plug π/12 in place of x? 

 

Can you show the steps please?  Thanks.

Answer 1

Hi Cece,

        There are two ways to verify if π/12 is a solution. The easiest way is substitute π/12 in the equation.

4*cos²(4*π/12)-3=4*(1/4)-3=-2 which is not zero so you can conclude that π/12 is not a solution and the answer is false.

The other way is to solve the equation for x and see if it is equal to π/12.

 

Hope this helps 

 

Jim

Answer 2

4cos²(4x) - 3 = 0

4cos²(4x) = 3

cos²(4x) = 3/4

cos(4x) = ±√3 / 2

4x = ±π/3

x = ±π/12

 

Yes, π/12 is a solution.