What is a neural network?
A neural network is an algorithm that can be used in machine learning, where a computer learns to complete a task by finding patterns in large volumes of data. The neural network is made up of multiple layers of individual nodes, which are areas where data is passed into at each layer. These nodes can be connected to several other nodes: they can be connected to the previous layer and receive data, and be connected to nodes in the next layer and feed further nodes data. Data is first fed into the input layer, and is then passed to the next layer, and so on and so forth depending on the number of layers. This process is called feed-forward, as data is moving through the network in a single direction. When data passes through these layers and each node receives an incoming connection, it will assign a number known as a weight. When data is passed through each node, the node will multiply the weight by the incoming value. If this value is below a certain threshold value, it will not pass the data, but if it is greater than the established threshold value, it will pass this data to the next node and repeat this process. Initially, the weights are randomly established, so its accuracy will be poor. But, through the training process, these weights are automatically adjusted to ensure that the accuracy is increasing. This is by far the best performing machine learning algorithm so far, because of how much data it can handle, and how efficiently it can be trained to solve problems such as image recognition, natural language processing, etc.
What is the area of a circle with a diameter of 14?
In the question, we are given the diameter. The unknown in this question is the area, and we know that the formula for the area of a circle is pi*r^2. In order to get the radius of the circle, we simply need to divide the diameter by 2, because the diameter is the distance from one end of the circle to the other. The radius is the distance from the midpoint to any point on the circle, so dividing the diameter by 2 will yield the radius. From here, we can substitute 7 for the radius in the area formula, and find the answer to be 49pi.
How is the ACT different than the SAT? Which should I take?
The ACT and SAT both have similar sections in reading, math, english/writing, and an essay, and the ACT has an added section of science. However, what these sections contain can be very different. In the ACT and SAT, the English/grammar section are both fairly similar: they test basic grammatical concepts, such as comma placement, word choice, etc. The ACT is much longer, at 75 questions, whereas the SAT is only 44 questions. The reading on the ACT and SAT are polar opposites. On the SAT, you have 65 minutes to do 52 questions (5 passages), but on the ACT, you have 35 minutes to do 40 questions (4 passages). Obviously on the ACT, you will have to work much faster than on the SAT. However on the ACT, the questions can be considered more straightforward. Every questions asked on ACT reading will have evidence in the passage to directly support it. The same is claimed for the SAT, but there can be more subjective questions. Math content covered in both tests is fairly the same, but the ACT has 60 questions in 60 minutes, and the SAT has a non calculator section, 20 questions 25 minutes, and a calculator section, 38 questions 55 minutes. From personal experience, I find the ACT math to be generally harder, due to some of the concepts in some of the questions that I have experienced. Finally, the ACT has a science section. In this section, students will need to analyze graphs and texts (mostly graphs) to answer questions about the passage. For the majority, you will not need prior knowledge about the topic at hand. Both standardized tests have an essay, however they are different. In the ACT, you will be presented with a situation, and you will have to give your stance on it and support it with evidence. The SAT is similar, but you will be given a passage, and you will need to deduce a meaning from the passage and use evidence to support how you know that this is the meaning. In terms of which test you should take, I would say take the ACT if you are more STEM oriented, and the SAT if you are more literature oriented. Personally, I struggled on the reading section in the SAT, so transitioning to a more straightforward reading section on the ACT and increased difficulty of math and science was much easier to handle. However, I would advise taking both once and seeing how you feel about each, and make a decision from there. I would highly NOT advise you to make assumptions about one or the other without taking it first hand.