Solve for x cos(x)=-1

Problem

cos(x)=−1

Solution

1. Identify the values on the unit circle where the x-coordinate is equal to −1

2. Determine the principal angle in the interval [0,2*π) that satisfies the equation, which is x=π

3. Generalize the solution by adding integer multiples of the period of the cosine function, which is 2*π

4. Write the solution using an integer k to represent all possible values of x

Final Answer

cos(x)=−1⇒x=π+2*k*π,k∈ℤ

Want more problems? Check here!