Discuss the below:
Q: A street light is at the top of a 14 ft tall pole. A woman 6 ft tall walks away from the pole with a speed of 7 ft/sec along a straight path. How fast is the tip of her shadow moving when she is 40 ft from the base of the pole?
Centerville is the headquarters of Greedy Cablevision Inc. The cable company is about to expand service to two nearby towns, Springfield and Shelbyville. There needs to be cable connecting Centerville to both towns. The idea is to save on the cost of cable by arranging the cable in a Y-shaped configuation. Centerville is located at in the -plane, Springfield is at , and Shelbyville is at . The cable runs from Centerville to some point on the -axis where it splits into two branches going to Springfield and Shelbyville. Find the location that will minimize the amount of cable between the 3 towns and compute the amount of cable needed. Justify your answer.
To solve this problem we need to minimize the following function of :
We find that f(x) has a critical number at
To verify that f(x) has a minimum at this critical number we compute the second derivativef'(x) and find that its value at the critical number is a positive number.
Thus the minimum length of cable needed is Use Newton's method to approximate a root of the equation as follows. Let be the initial approximation. The second approximation is and the third approximation is