Go-Back-N (GBN) and Selective Repeat (SR). Suppose window size be 16. Only the 8th packet is lost during transmission. Assume the following: • Packet transmission delay be A, timeout interval be B, and round-trip delay be C. • The path is symmetric in terms of delay. • Timeout is greater than the time to send 16 packets plus the round trip time. • The ACK transmission delay is negligible. How much time will it take to send all 16 packets to the receiver by each protocol? Express the equation using notations mentioned here such as A, B, and C.

Write lines of verse that rhyme to remember the following information: acid rain is a type of air pollution caused by chemicals in the air.

Which of the following statements is false? a. a class can directly inherit from class object. b. if the class you're inheriting from declares instance variables as private, the inherited class can access those instance variables directly. c. a class's instance variables are normally declared private to enforce good software engineering. d. it's often much more efficient to create a class by inheriting from a similar class than to create the class by writing every line of code the new class requires.

Write a program that displays the following menu: geometry calculator 1. calculate the area of a circle 2. calculate the area of a rectangle 3. calculate the area of a triangle 4. quit enter your choice (1-4): if the user enters 1, the program should ask for the radius of the circle and then display its area. use the following formula: area = ď€(the square of r) use 3.14159 for ď€ and the radius of the circle for r. if the user enters 2, the program should ask for the length and width of the rectangle and then display the rectangle’s area. use the following formula: area = length * width if the user enters 3, the program should ask for the length of the triangle’s base and its height, and then display its area. use the following formula: area = base * height * .5 if the user enters 4, the program should end. input validation: display an error message if the user enters a number outside the range of 1 through 4 when selecting an item from the menu. do not accept negative values for the circle’s radius, the rectangle’s length or width, or the triangle’s base or height. note: if the user enters an improper menu choice (1-4), the program prints "the valid choices are 1 through 4. run the program again and select one of those." if the user enters a negative radius, the program prints "the radius can not be less than zero." if the user enters a negative value for height or base, the program prints "only enter positive values for base and height."