Need help with Complex Variables, the Real Number System, Complex Numbers, Dot and Cross Products, Limits, Derivatives, Continuity, Taylor's Series, Integrals? This study guide has more than 600 well-illustrated, carefully worked out and explained examples to sharpen your problem-solving skills. I have tutored students in mathematics and science for more than 30 years. A good tutor or teacher can help a struggling student pass a class that the student might fail. A good tutor can also help a strong student do much better in a class than he or she might otherwise do.