Sean Luck, Founder

Randolph, WI

## Student Testimonials:

### Lecture: Definition of the Derivative

OMG WHOEVER INVENTED THIS IS FREAKIN AMAAZING!!! best idea i've seen in a while!
-at7667a

### Lecture: Rigorous Derivative of Sin x

thank you so much! i kept getting stuck in the part when you can separate the cos and sin with the denominator h (i didn't think about that). :D
- danielapimentel43

### Lecture: Definition of the Derivative

you are the best man, it took my 3 years to understand﻿ that on my on, here i understud in 3 minuts :P thanx :P
-kingfker

### Lecture: Question: Is Y a Function of X

Great, just what I needed, a simple quick explanation. THANK YOU!
- comp1337n00b

### Lecture: Basic Derivative Rules

Godd tutorial! Altough english is not my native language you explain it very clearly and structured. Many thanks!
- Fangornmmc

### Lecture: Problem 4 Solving 1/x Using the Definition of the Derivative

thank u so much! i was having trouble with the denominators in the numerator and getting rid of h, and this video totally straightened me out! :)
- AFBMovies

### Lecture: Definition of the Derivative

I've been looking for this, thanks! you should﻿ make more videos and help alot more people : ]
-underzikefu

### Lecture: Rolle's Theorem / Mean Value Theorem

thank you u﻿ are so awsome
-eba23

### Lecture: Definition of the Derivative

wow...this is lovely - man u add a new dimension to﻿ my view of derivatives!!! thanx a ton!
- laughingjal

### Lecture: Definition of the Derivative

I like the way you present﻿ the topic. It is a lot easier to grasp with the animations and the simple example. Simple and effective! :)
-jkwesiga

### Lecture: Trigonometric Derivatives

Thank﻿ you! I have been looking for this everywhere! Everyone is showing examples and all I wanted was a list of what is the derivative of what. THANKS!
-BowlingForChickens