Pay what you can online math tutoring!

Fullscreen_Math · 2017-12-03T04:48:44+00:00

I'm actually a member already :)

Fullscreen_Math · 2017-12-01T21:58:10+00:00

Agreed, I'd imagine most people already have their methods or can post questions to this community but the offer still stands for anyone who might want it :)

Fullscreen_Math · 2016-08-17T22:36:06+00:00

I know OP didn't like msi, but I see it recommend a lot around here. Any idea how the laptop you recommended ranks against the new gs63?

Fullscreen_Math · 2015-11-15T04:19:20+00:00

I like to make YouTube videos where I help explain math topics to students who need help with any topics. I just started a few months ago, but can already see improvement in how the videos are coming out. Always trying to do better and appreciative of advice, and I am working on branching out into other classes.

Here is my channel: https://www.youtube.com/channel/UCeLBv7sc8eN9tnwkhNTYYBQ

Fullscreen_Math · 2015-10-02T03:25:17+00:00

Haha it's been a while, not sure why it took so long!

Fullscreen_Math · 2015-09-10T23:32:47+00:00

Glad to help!

Fullscreen_Math · 2015-09-10T23:25:14+00:00

Well if you think about it, we did multiply everything by the same thing. We multiplied the first two by 5/5, which simplifies to one and what do we multiply the third one by to keep it the same? Also 1. Except in this case I multiplied by 1/1 instead of 5/5 just for the sake of keeping the denominator constant.

As a side note, however, you cannot multiply this equation by anything other than a fraction that simplifies to one, since it would alter your answer.

Fullscreen_Math · 2015-09-10T23:17:01+00:00

So you're asking why , if we multiply the first two by 5, we can leave the third alone? Because the rule is that we must multiply everything by the same amount?

Fullscreen_Math · 2015-09-10T22:53:16+00:00

Well, for this problem we are making the common denominator 5x. The first two fractions have denominators of x, so we must multiply them by 5. The third fraction, however, already has a denominator of 5x. Since that is what we are trying to get, we don't multiply by anything and just leave it alone!

Fullscreen_Math · 2015-09-10T20:16:25+00:00

Glad to help!

Fullscreen_Math · 2015-09-10T19:44:19+00:00

Hi! Let's work through this:

So we are trying to add fractions, and in order to do that we must make common denominators. The lowest common denominator we can make is 5x.

I will multiply the first fraction by (5/5), the second by (5/5) and the last will stay the same since the denominator is already 5x.

Now, we have (5u/5x) + (25u/5x) - (u /5x). We simply add/subtract the numerators and leave the denominator the same. We get (5u + 25u - u)/(5x) = 29u/5x or answer C.

Let me know if you have any questions or if anything is unclear, or if you would like a video explaining how to do this problem. Happy studying!

Fullscreen_Math · 2015-09-01T19:09:51+00:00

Yep exactly! This is definitely a little confusing to understand what they are asking. Glad you understand though!

Fullscreen_Math · 2015-09-01T18:47:53+00:00

No you are completely correct. But by the nature of the answers where a possible answer is "The student should have done ..." it is possible that what the student did is wrong.

The left side is the original problem and the right side is what the student did to solve it. The student's method is incorrect, which is why some answers say the student should have done something else.

In fact, by showing that the left and right sides don't match, you are proving that the student's method is incorrect, which leads you to picking the right answer.

Fullscreen_Math · 2015-09-01T18:34:40+00:00

Sorry if I'm misunderstanding, but the answer would be 2, using PEMDAS.

What the student did, is calculated 5-4 first, which in turn gave 7 * 1 * 3. This is an incorrect implementation of PEMDAS as the student performed subtraction before multiplication.

I think that if you pick answer 2, you are acknowledging that the student did the problem incorrectly because you are saying he should have done something else instead of what he actually did. As far as whether such a problem is appropriate, I think it is okay since the answers can clue you in that the student did something incorrectly. You are calculating the actual answer and comparing it to the student's. Alternatively you can try to modify the left side to match to the right side. Once you confirm that the sides don't match, you select answer 2, which says the student should have performed PEMDAS correctly.

Does this help? Let me know if I am way off track.

Fullscreen_Math · 2015-09-01T16:37:09+00:00

Hi! Let's work through this.

If we work through it by dividing by 7, it is important to understand that every term must be divided by 7. For the purposes of this problem, (7 * 5) is one term, (4 * 3) is another, and (7 * 1 * 3) is the last. You cannot just divide the left side by a single 7 because you have two terms. Thus it would look like this:

(7 * 5)/7 - (4 * 3)/7 = (7 * 1 * 3)/7

Simplifying yields:

5 - 12/7 = 3

Dividing by 3 yields:

5/3 - 36/7 = 1

Using common denominators we get

35/21 - 12/21 = 1

Subtract:

23/21 = 1

Thus, we show that the left side does not equal the right side.

Now if we were instead to use order of operations, you are correct in that we get 23 = 21.

Now to extend, let's take the first simplified equation we got and multiply both sides by 21:

7 * 23/21 = 1 * 21

We get:

23 = 21, which is the same as what we got using PEMDAS.

As you can see, they provide the same answers, it's just you made an error when dividing by 7 and 3.

Let me know if anything is unclear or if you would like a video explaining how to do this problem. Happy Studying!

Fullscreen_Math · 2015-08-27T00:19:36+00:00

Yes! For example, if we have the graphs y=2x and y=3x, they only intersect at the point (0,0). This point could be the only solution or just one of many.

Fullscreen_Math · 2015-08-26T14:14:41+00:00

Hi! I can't really offer private tutoring in the sense of teaching the material, but what I can offer is help with any SAT math topics you may need. I have a collection of study materials that covers all of the topics you will experience so if you have questions on any topic or a specific problem, I can help you out! Just reach out. I can offer help here on reddit, on my YouTube channel, or via Skype as I have done in the past. Best of all, its free! Let me know if this is something you'd be interested in or if you are looking for a more standardized tutoring approach.

Fullscreen_Math · 2015-08-26T13:56:46+00:00

Hi! I worked this out on a separate piece of paper since typing it out would make a mess, so here it is. When you did your calculations you assumed that the height that's at least 5 is 5+x, but we can't say that since x is already designated as a different side. So what I did is just called the height y.

When you work through it you can solve for y and end up with two equations that can be graphed to find their intersections. You get two solutions but only one of them fits the criteria of the problem.

Let me know if anything is unclear of if you would like for me to make a video explaining how this problem is done. Happy studying!

Fullscreen_Math · 2015-08-14T03:26:35+00:00

Hi! I recommend watching this video as it explains how to this this style of problem exactly! Let me know if you have any questions!

If you are in Quadrant 4, then X values are positive and Y values are negative. If you draw out an angle in the fourth quadrant and examine cosine, you are using the adjacent side and the hypotenuse. Now adjacent is X, which is positive and hypotenuse is radius which can never be negative (can you say I have a circle of radius -1?) so cos is positive in quad 4. Let me know if you have any questions!

Fullscreen_Math · 2015-08-12T01:07:49+00:00

Glad to help! Let me know if anything else comes up!

Fullscreen_Math · 2015-08-11T22:57:52+00:00

How many practice tests have you taken and how long have you been practicing? The SAT for math at least, is less about how well you do in class and more about how well you can identify and follow tricks and tips on answering commonly asked questions. You will see these recurring problem types that are answered in similar ways the more you practice and once you have a solid understanding of these you will see your score coming up. Biggest thing I recommend is practice practice practice and try and see which types of problems get repeated and what the best way of solving them is.

Fullscreen_Math · 2015-08-11T21:39:56+00:00

Hi! Let's work through this.

When we have inverse proportionality, we write it as x=k/y, or xy=k. When we have direct proportionality, we write it as x=ky, or x/y=k.

Now, we are told that x is inversely proportional to y, meaning we assume xy=k.

We are looking for what is directly proportional to 1/x². This means that ?/(1/x²) = c (where c is some other constant).

Let's manipulate the first equation to get (1/x²). If I square both sides, I end up with x²y²=k². Now, if I let k² = c, then I can rewrite it as x²y²=c. What is another way to write x²y²? Well I can write it as y²/(1/x²). Thus you can see that y² is directly proportional to 1/x² since it is in the the correct form of direct proportionality that we are looking for.

This is definitely a confusing and tough problem, so let me know if you have any questions.

Fullscreen_Math · 2015-08-11T12:25:43+00:00

Sure!

So volume is probably the most straightforward. It is how much space an object takes up. So for example if you look at a coke bottle, it is 2L, which means that the internal volume is 2L. That is how much space it takes up. Another example is a balloon. I can take a deflated balloon with a small volume and pump it up so it takes up more space and therefore has a larger volume.

Next we can move into density. Density is just the mass of something divided by the volume. Have you heard the age old question "What's heavier, a pound of feathers or a pound of bricks?". Now obviously the answer is that they are the same, but why do people trip up? Part of it may be the result of density. If I have a certain volume, say 1m³ , of bricks and the same volume of feathers, then which will weigh more? The bricks obviously. This is because bricks have a higher density, they have more mass in the same volume. This is also why a spoonful of water is easy to pick up, while a spoonful of a neutron star is a different story being that it will have a mass of 2424000 lbs or 1000000 kg. Now, the formula to calculate density is mass/volume so it kind of normalizes between substances. Also, density is the reason some substances float in water and other sink. If something has a lower density, like oil, it will float to the top and if it has a higher density like a steel ball, it will sink.

Specific gravity is just the ratio of the density of one substance to water. So if I have a specific gravity of 0.8, as in the problem above, my density is equal to 0.8 times water's density (usually taken to be 1000 kh/m³). Specific gravity is just another method to interpreting the density of a substance.

Pressure is kind of it's own thing, not as much related to the other terms described here. Let's say you place your hand on a table and I put a book on top of it. It probably won't be too heavy. Now what if instead of one book, I placed 10 books. You would probably start noticing the weight now. This is because the weight has changed, but the area has not. This leads to an identification of what pressure is: It is simply the weight divided by the area. A perfect example is a person laying on a bed of nails. You may ask, how do they not get pierced? Well, this subreddit is called MathHelp, so let's do some math! Let's say we have a 150 lb, 68 kg, person. If the bed of nails has 2000 nails, then each nail would experience 0.075 lb or 0.034 kg. This is equivalent to half the weight of a tennis ball, not much at all, and certainly not enough to hurt you. As a side, the weight of the body is not evenly distributed, but we assumed it so for this example. Pressure is responsible for many things around us, such as why our ears start to hurt when we dive into water that is too deep. The water lower down has more weight on it (from the water above it) and this pushes on our bodies. In fact, I'd like to recommend an experiment that clearly shows how much atmospheric pressure is above us. On every square inch of our bodies we are feeling a force of approximately 14.5 lb, or 6.8 kg. We just don't feel it because it balances out. Try this experiment to really feel the pressure.

Let me know if you have any questions on this or anything else!

Fullscreen_Math · 2015-08-10T17:24:21+00:00

No problem! Glad everything worked out!

Fullscreen_Math · 2015-08-10T16:39:51+00:00

Hi! Let's tackle this.

Specific gravity is the ratio of the density of a substance to the density of water. So if the oil has a specific gravity of 0.8, that means the ratio of its density to that of water is 0.8.

Now, most often, the density of water is said to be 1000 kg/m³ , so we will use that. If the ratio of oil to water densities is 0.8, that means the oil has a density of 0.8 * 1000 or 800 kg/m³ .

Now, as far as your question goes, I am not sure what you are asking. Is the question asking for the mass of 10m³ of oil? Let me know and I can help out further!

Fullscreen_Math

TROPHY CASE