Questions: Solve the equation over the interval [0,2 π). Write numbers using integers or simplified fractions.
(a) cos α = -√3/2
(b) cos α = √3/2
Transcript text: Solve the equation over the interval $[0,2 \pi)$. Write numbers using integers or simplified fractions.
(a) $\cos \alpha=-\frac{\sqrt{3}}{2}$
(b) $\cos \alpha=\frac{\sqrt{3}}{2}$
Solution
Solution Steps
Step 1: Solve \(\cos \alpha = -\frac{\sqrt{3}}{2}\) over \([0, 2\pi)\)
The cosine of an angle is \(-\frac{\sqrt{3}}{2}\) at \(\alpha = \frac{5\pi}{6}\) and \(\alpha = \frac{7\pi}{6}\) in the interval \([0, 2\pi)\).
Step 2: Write the solution set for \(\cos \alpha = -\frac{\sqrt{3}}{2}\)
The solution set is \(\left\{\frac{5\pi}{6}, \frac{7\pi}{6}\right\}\).
Step 3: Solve \(\cos \alpha = \frac{\sqrt{3}}{2}\) over \([0, 2\pi)\)
The cosine of an angle is \(\frac{\sqrt{3}}{2}\) at \(\alpha = \frac{\pi}{6}\) and \(\alpha = \frac{11\pi}{6}\) in the interval \([0, 2\pi)\).
Step 4: Write the solution set for \(\cos \alpha = \frac{\sqrt{3}}{2}\)
The solution set is \(\left\{\frac{\pi}{6}, \frac{11\pi}{6}\right\}\).