6. Trigonometric Identities and More Equations

6. Trigonometric Identities and More Equations / Solving Trigonometric Equations Using Identities / Problem 2

Solve the following trigonometric equation on the interval [0, 2π) with the help of an identity.
cos 2x + 3 cos x + 1 = 0

3π/2

0, π/2, 3π/2

π/2, 3π/2

π/2

Solve the following trigonometric equation on the interval [0, 2π) with the help of an identity.cos 2x + 3 cos x + 1 = 0