#1
i need some help with a related rates problem in a calc review packet i got. the test is tomorrow, so any help would be greatly appreciated.

An observer is standing underneath a kite. He is 100ft away from the kite flyer. The kite moves horizontally at a speed of 8ft/s. At what rate is the angle between the string and the horizontal decreasing when 200ft of string have been let out?

Here's the signs I've assigned:

x = distance between the two people = 100
y = how high the kite is = 100*√3
s = length of string = 200ft

dx/dt = 8ft/s
dy/dt = 0
ds/dt = ?
dtheta/dt = ?

PS: As an all-too-important sidenote, the triangle formed is a 30/60/90. The angle whose rate of decrease I need to find is the 60.

PPS: We haven't learned how to derive arccos yet, or I'd already be done with this.
#3
1/2b*h?
except change that with x and y. take the derivative with respect to time. then plug in the values. solve for dy/dt
PS3

Fear the LIME

X
#5
Quote by marktuazon
1/2b*h?
except change that with x and y. take the derivative with respect to time. then plug in the values. solve for dy/dt

i'm not going for area, i'm going for the angle of the string to the ground. plus i already know that dy/dt is 0, since the height of the kite isn't changing.
#8
I'd love to help you if you draw me a diagram if there is one with the question.
Quote by blynd_snyper
yes we all need answers to xboys questions hurry up goddam it


Quote by Kankuro
Damn you X-Boy!!!


Founder And Member Of The " I Don't Masturbate Club "

TURNED 18 TODAY !!! (22/02)