Question

Solve the equation cos2x = -1\2, for 0 < x < 360°.​

Answer 1

Answer:

x = 60°, 120°

Step-by-step explanation:

If we let $t=2x$, our equation now becomes $\cos{t}=-1/2$, which is true for two values of t: 120° and 240°. Since t = 2x, we can say that $120^{\circ}=2x$ and $240^{\circ}=2x$, and therefore $x = 60^{\circ}$ and $x=120^{\circ}$