Problem

Find the value of x if cos(2x)=12 and x3+1=0

Answer

Expert–verified
Hide Steps
Answer

The final step is to find the common solutions to both equations. The only common solution is x=1, which corresponds to n=1 in the first equation.

Steps

Step 1 :First we solve the equation cos(2x)=12. The general solution to this equation is x=π3+2nπ or x=π3+2nπ, where n is an integer.

Step 2 :Next, we solve the equation x3+1=0. This is a sum of cubes equation. It can be factored into (x+1)(x2x+1)=0. Setting each factor equal to zero gives us x=1 or x2x+1=0. The second equation has no real solutions, so x=1 is the only solution to this equation.

Step 3 :The final step is to find the common solutions to both equations. The only common solution is x=1, which corresponds to n=1 in the first equation.

link_gpt