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Home » A ladder 5 cm long is leaning against a wall. The bottom of the ladder is pulled along the ground, away from the wall, at the rate of 2 cm/s. How fast is its height on the wall decreasing when the foot of the ladder is 4 m away from the wall?
A ladder 5 cm long is leaning against a wall. The bottom of the ladder is pulled along the ground, away from the wall, at the rate of 2 cm/s. How fast is its height on the wall decreasing when the foot of the ladder is 4 m away from the wall?
Applications of Derivatives | CBSE | Class 12 | Exercise 6.1 | Maths | NCERT
A ladder 5 cm long is leaning against a wall. The bottom of the ladder is pulled along the ground, away from the wall, at the rate of 2 cm/s. How fast is its height on the wall decreasing when the foot of the ladder is 4 m away from the wall?

Let AB be the ladder and C is the junction of wall and ground, AB = 5 m  B

Let CA =  meters, CB =  meters

According to the equation,

 increases,  decreases

and  = 2 cm/s

In AC2 + BC2 = AB2  [Using Pythagoras theorem]

   ……….(i)

 

 

 

  ……….(ii)

When 

 [From eq. (i)]

 From eq. (ii),   cm/s

i

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