st client_x_step = (w/(x_max-x_min));
	const client_y_center = h - h*(0-y_min)/(y_max-y_min);
	const client_y_step = (h/(y_max-y_min));

	function client_to_x(client_x){
		return (client_x - client_x_center) / client_x_step;
	}

	function client_to_y(client_y){
		return (client_y_center - client_y) / client_y_step;
	}

	function x_to_client(x){
		return x * client_x_step + client_x_center;
	}

	function y_to_client(y){
		return client_y_center - y * client_y_step;
	}

	plot = document.getElementById("tan");