Related Rates - The Shadow Problem

This calculus video tutorial explains how to solve the shadow problem in related rates. A 6ft man walks away from a street light that is 21 feet above the ground at a rate of 3ft/s. At what rate is the length of the shadow changing?

Introduction to Limits:
https://www.youtube.com/watch?v=YNstP0ESndU

Derivatives - Fast Review:
https://www.youtube.com/watch?v=5yfh5cf4-0w

Introduction to Related Rates:
https://www.youtube.com/watch?v=I9mVUo-bhM8

Derivative Notations:
https://www.youtube.com/watch?v=7BK_mmYckmI

Related Rates - The Cube:
https://www.youtube.com/watch?v=r5PTN2TgGwc

__________________________________
Inflated Balloon & Melting Snowball:
https://www.youtube.com/watch?v=8dm0UtPyYj8

Gravel Dumped Into Conical Tank:
https://www.youtube.com/watch?v=xvbrEfVLQ4k

Related Rates - Area of a Triangle:
https://www.youtube.com/watch?v=RGRhinA7YDI

Related Rates - The Ladder Problem:
https://www.youtube.com/watch?v=W3qoQIlfG0E

Related Rates - The Distance Problem:
https://www.youtube.com/watch?v=_sbq6yZ9Kt8

____________________________________
Related Rates - Airplane Problems:
https://www.youtube.com/watch?v=jUn8MpV80po

Related Rates - The Shadow Problem:
https://www.youtube.com/watch?v=-En2IABPR0I

Related Rates - The Baseball Diamond Problem:
https://www.youtube.com/watch?v=zytwFSyH0_0

Related Rates - The Angle of Elevation Problem:
https://www.youtube.com/watch?v=dUBeikdfK10

Related Rates - More Practice Problems:
https://www.youtube.com/watch?v=ps-r4nti5Go

_________________________________
Final Exams and Video Playlists:
https://www.video-tutor.net/

Full-Length Videos and Worksheets:
https://www.patreon.com/MathSc....ienceTutor/collectio