Friday

August 29, 2014

August 29, 2014

Posted by **Tanya** on Friday, November 23, 2012 at 3:33pm.

- Calculus! -
**Steve**, Friday, November 23, 2012 at 6:23pmI suspect a typo somewhere. When the ladder is lying flat at t=3, the base is no longer moving.

- Calculus! -
**Reiny**, Friday, November 23, 2012 at 6:36pmMake a sketch:

x^2 + y^2 = 256

when t=0 , y=12, x = √112

when t = 1, y = 8 , x = √192

when t = 2 , y = 4 , x = √240

when t = 3, y = 0, x = √256 = 16

given dy/dt = -4 ft/s

2x dx/dt + 2y dy/dt = 0

dx/dt = -y (dy/dt) / x

= 0/16 = 0

check:

let t=1

y = 8, y = √192

dx/dt = -8(-4)/√192 = appr 2.3

let t = 2

y = 4, x = √240

dx/dt = -4(-4)/√240 = appr 1.03

slowing up ....

let t = 2.99 sec

y = 12 - 2.99(4) = .04 , x = √255.9984

dx/dt = -.04(-4)/√255.9984 = appr .01 (close to zero)

**Related Questions**

Math - A ladder leans against a vertical wall and the top of the ladder is ...

Calculus - 1a. 15 ft ladder is placed against a vertical wall. the bottom of the...

Calculus - A 15 ft ladder is placed against a vertical wall. the bottom of the ...

CALCULUS - A 25 ft ladder is leaning against a vertical wall. At what rate (with...

math - A ladder 10 m long rests on horizontal ground and leans against a ...

math - A 16-ft ladder is sliding down a wall as shown in the figures below. The ...

Calculus - A ladder 15 feet long leans against a vertical wall. Supppose that ...

calculus - : A 20m ladder is placed against a wall. The bottom of the ladder is ...

mathematic - A ladder 10 meter long is leaning against a wall. If the top of ...

Math - A 15 ft ladder leans against a wall. The bottom of the ladder is 3 ft ...