AP CALC AB Essay question:
A streetlight, 20 feet in height, stands 5 feet from a sidewalk. A person, 6 feet tall, walks along the sidewalk at 4
ft/sec. At what rate is the length of the person’s shadow changing when the person is 13 feet from the base of the
street-light?

NOTE: This problem involves the use of a rigid and fluid model, of which the latter will produce a differentiable equation. (Both these models I have written down... I have little idea of what to do next)

Question

AP CALC AB Essay question:
A streetlight, 20 feet in height, stands 5 feet from a sidewalk.  A person, 6 feet tall, walks along the sidewalk at 4 
ft/sec.  At what rate is the length of the person’s shadow changing when the person is 13 feet from the base of the 
street-light?

NOTE: This problem involves the use of a rigid and fluid model, of which the latter will produce a differentiable equation. (Both these models I have written down... I have little idea of what to do next)

anonymous · Answer

P.S. This is a RELATED RATES problem.