Question

Find θ to four significant digits for 0 < θ< 2 pi if cos θ= 0.6725

Answer 1

First, we need to solve for θ:

`\cos\theta=0.6725`
`\theta=\cos^(-1)(0.6725)`
`\theta=0.8332147`

But, since the cosine is a function that takes the same values every 3π/2, if we add this to the solution:

`\theta_2=0.8332147+(3\pi)/(2)\approx5.5456`

Thus, the two solutions are:

`\theta=0.8332,5.5456`