Problem

(a) Show that the equation $4x - 2\sin x - 1 = 0$, where $x$ is in radians, has a root $\alpha$ in the interval $[0.2, 0.6]$

(b) Starting with the interval $[0.2, 0.6]$, use interval bisection twice to find an interval of width $0.1$ in which $\alpha$ lies.