"Quadratic Equation
'<hr/>
f(x) = a*x^2 + b*x + c'= 0
'Coefficients:
a = ? {2}','b = ? {3}','c = ? {-5}
#hide
PlotWidth = 360''PlotHeight = 200
#post
#if a ≡ 0
	'The coefficient <i>a</i> is equal to zero. The equation is linear.
	x = -c/b
#else
	'Discriminant:
	D = b^2 - 4*a*c
	#if D ≥ 0
		'The discriminant is grater or equal to zero. Real roots exist.
		q = -0.5*(b + sign(b)*sqr(D))
		x_1 = q/a', ' _
		x_2 = c/q
		#hide
		d = abs(x_2 - x_1)/4
		x_min = min(x_1; x_2) - d
		x_max = max(x_1; x_2) + d
		#post
		$Plot{f(x) & x_1|0 & x_2|0 @ x = x_min : x_max}
	#else
		'The discriminant is less than zero. There are no real roots.
		#hide
		d = -b/(2*a)
		x_min = d + abs(a)
		x_max = d - abs(a)
		#post
		$Plot{f(x) @ x = x_min : x_max}
	#end if
#end if 