what is wrong with my script?

An error keeps on popping up. The error is: CS0839 and it says that an argument is missing but I don’t know what that is.

using UnityEngine;
using System.Collections;

public class playercontrols : MonoBehaviour 
{
	void fixedUpdate ()
	{
		float h = horizontalSpeed * Input.GetAxis("Mouse X");
		float v = verticalSpeed * Input.GetAxis("Mouse Y");

		Vector3 movement = Vector3(horizontalSpeed, 0.0f, verticalSpeed,);

		rigidbody.AddForce(movement);
	}
}

You have an extra comma on line 11 which would be you specifying that there is another parameter to the Vector3.

Vector3 movement = Vector3(horizontalSpeed, 0.0f, verticalSpeed,);

should be:

Vector3 movement = new Vector3(horizontalSpeed, 0.0f, verticalSpeed);