What is something a that a vacuum tube cannot do?

a. change alternating current into direct current
b. increase the strength of a signal
c. convert electrical energy into thermal energy
d. turn a current on or off

Write a program that prompts the user to input a string. the program then uses the function substr to remove all the vowels from the string. for example, if str = "there", then after removing all the vowels, str = "thr". after removing all the vowels, output the string. your program must contain a function to remove all the vowels and a function to determine whether a character is a vowel.

How do you take a green screen out of the video while editing?

Consider the series where in this problem you must attempt to use the ratio test to decide whether the series converges. compute enter the numerical value of the limit l if it converges, inf if it diverges to infinity, minf if it diverges to negative infinity, or div if it diverges but not to infinity or negative infinity.