Question

Find θ for 0 degrees < θ < 360cos θ= -0.28, tan θ>0

Answer 1

Given:

`\begin{gathered} \cos\theta=-0.28 \\ \\ \tan\theta>0 \\ \\ 0<\theta<360 \end{gathered}`

Find: Value of angle.

Sol:

`\begin{gathered} \cos\theta=-0.28 \\ \\ \theta=\cos^(-1)(-0.28) \\ \\ \theta=106.2602,253.7398 \end{gathered}`

Check for tan then:

`\begin{gathered} \tan\theta>0 \\ \\ \tan(106.2602)=-3.4 \\ \\ \tan(253.7398)=3.4 \end{gathered}`

So the angle value is only 253.74