Locate and bisect a circular-equation root
A numerical root is required for the following equation
\[\sin x=-0.565\]
Write the algebraic function in the equation as \(P(x)=-0.565\)
Let \(F(x)\) be the circular side minus the algebraic side, so \(F(x)=\sin x-\left(-0.565\right)\)
The sign-changing interval under consideration is \(\left[-\frac{9}{10},-\frac{2}{5}\right]\). The table also gives one point just outside each endpoint
| \(x\) | \(F(x)\) |
|---|---|
| \(-\frac{41}{40}\) | \(\approx -0.290\) |
| \(-\frac{9}{10}\) | \(\approx -0.218\) |
| \(-\frac{2}{5}\) | \(\approx 0.176\) |
| \(-\frac{11}{40}\) | \(\approx 0.293\) |
Use the endpoint signs in the table to identify what can be concluded about a root
Select the two functions, the justified root count and the interval containing the sign change