http://www.youtube.com/watch?v=S2CaKzKz_pw&feature=youtu.be
powerful tangent line finder with up to 4 terms in a function, step by step, by Tom Owsiak, Atlanta, GA, 5/17/2013
www.livingcalculus.com
www.livingalgebra.com
watch this video to learn how to use most of the features
http://www.youtube.com/watch?v=S2CaKzKz_pw&feature=youtu.be