The Newton – Raphson method is used to find the roots of the equation

$f(x) = x- \cos\pi x$                            $0\le x\leq1.$

If the initial guess for the root is $0.5$, then the value of $x$ after the first iteration is

1. $1.02$
2. $0.62$
3. $0.55$
4. $0.38$