Bisection<-function(func,x_left,x_right,accurary=0.001)
{
	if (f(x_left) * f(x_right)>0){
		cat("Two end points have the same sign! Cannot use bisection\n")
		return
	}
	iter = 1
	while(x_right-x_left>accurary)
	{
		x_mid = (x_left+x_right)/2
		cat("Iteration ", iter, " x=", x_mid, "\n");
		iter=iter+1
		if (f(x_mid)*f(x_left)>0) { #mid has same sign as left, then search right
			x_left = x_mid
		} else { 
			x_right = x_mid
		}
	}
}
Newton <-function(func, funcPrime, x ,accurary=0.001)
{
	x_old = x
	iter = 1
	while(TRUE)
	{
		x_new = x_old - func(x_old)/funcPrime(x_old)
		cat("Iteration ", iter, " x=", x_new, "\n");
		if (abs(x_new - x_old)<accurary) {
			break;
		}
		if (abs(x_new-x_old)>1000) {
			cat("Newton's method seems to diverge\n");
			break;
		}
		if (iter>1000) {
			cat("No solution after 1000 iterations.\n");
			break;
		}
		x_old = x_new
		iter = iter+1
	}
}
f<-function(x) {return(x^3-x-2)}
fprime<-function(x) {return(3*x^2-1)}
Bisection(f,0,1)
Newton(f,fprime,2)
Newton(f,fprime,0)