Use a calculator to solve the equation on the interval 0 $0 \leq \theta

Question

Use a calculator to solve the equation on the interval 0 $0 \leq \theta < 2 \pi$ . Round the answer to two decimal places.
-$\cos \theta = - 0.55$
A) 2.15, 4.13
B) 0.99, 2.15
C) 0.99, 4.13
D) 2.15, 5.29

Quizplus · Accepted Answer

The cosine function is negative in the second and third quadrants. To find the angles, we first find the principal value $\theta = \cos^{-1}(-0.55)$, which gives $\theta \approx 2.15$ radians. The second solution within the interval $0 \leq \theta < 2\pi$ is found by subtracting this value from $2\pi$, giving $2\pi - 2.15 \approx 4.13$ radians.

Use a Calculator to Solve the Equation on the Interval 0≤θ<2π0 \leq \theta < 2 \pi0≤θ<2π

Use a Calculator to Solve the Equation on the Interval $0 \leq \theta < 2 \pi$