Derivação implícita, derivadas direcionais e vetor gradiente

Derivação implícita:

http://www.youtube.com/user/v13dinei?feature=mhee#p/search/0/AuimxolflCQ
http://www.youtube.com/user/v13dinei?feature=mhee#p/search/1/4yMwxZ5kOh0
http://www.youtube.com/user/v13dinei?feature=mhee#p/search/2/2Zjy7yTqQLI

Derivadas direcionais e vetor gradiente:

http://www.youtube.com/watch?v=w2ZuwX5cKlM
http://www.youtube.com/watch?v=IWFOPzgrZT4&feature=related
http://www.youtube.com/watch?v=sYbo-pb9pp0&feature=related
http://www.youtube.com/watch?v=w2ZuwX5cKlM&feature=related
http://www.youtube.com/watch?v=xkH0fbvdk5k&feature=related
http://www.youtube.com/watch?v=iep386F_nVs&feature=related
http://www.youtube.com/watch?v=dagmVbXQAZA&feature=related
http://www.youtube.com/watch?v=0UffIUg8PME&feature=related
http://www.youtube.com/watch?v=9Bofi3wNEnU&feature=related
http://www.youtube.com/watch?v=4iav2CK3q2w&feature=related
http://www.youtube.com/watch?v=bENWnwOYVrM&feature=related
http://www.youtube.com/watch?v=j9Wtu5Kh4uQ&feature=related
http://www.youtube.com/watch?v=4DGHKbtNlJc&feature=related
http://www.youtube.com/watch?v=MQOuVXLatyk&feature=related
http://www.youtube.com/watch?v=rZJvYwCSfaE&feature=related