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Advanced Math/Questions Answered by Expert David Hemmer
| Subject | Date Asked |
| power laws | 12/30/2011 |
| Q: If the number of people(N) with wealth (W) is related to the inverse of W raised to a power between ... A: Your first sentence gives an equation like: N= 1/(W^x) where x is between two and three. If that ... | |
| Systems | 1/2/2011 |
| Q: So I'm a junior in High School and I'm in Advanced Algebra and Trig, & I've been having a little ... A: Since you hopefully know how to solve problems like 4x+9=14 the goal is to turn your system into an ... | |
| David Essner | 1/2/2011 |
| Q: Hemmer, I am a 14 year old in high school and I was practicing for the David Essner math finals by ... A: Your proof has a little confusion about relatively prime. Relatively prime means the GCD is 1, so ... | |
| Simultaneous inequalities | 12/30/2010 |
| Q: Having trouble solving the following problem. I'm a degree student working on a concept from an ... A: The easiest way is to look at the equalities: j+.5k=3.5 j+.5k=.5 These are two parallel lines in ... | |
| 360/360 simple interest | 12/28/2010 |
| Q: I got myself involved in a loan with a national company that for a $2600 loan,they charge 96% ... A: Simple interest is just as it describes, you are paying interest each day, assuming each year has ... | |
| logarithmic differentiation | 9/27/2010 |
| Q: Need to find dy/dx this is not a homework problem ln y = (e^y)sin(x) I took the Ln of both sides to ... A: You can do this without talking ln first: (1/y) y' = e^y*y'*sin(x) + e^ycos(x) y'=y(e^y*y'*sin(x) ... | |
| chemistry/mole problems | 10/29/2009 |
| Q: i'm doing a project on: one mole of crayons would make ?? number of trips to the sun and back. ... A: What exactly to you need help with? If a crayon is 6" long and a mole is 6.022*10^23 then a mole of ... | |
| Epsilon-delta proof | 10/28/2009 |
| Q: Can you please help me with an epsilon delta proof of two variables? I need to prove the limit of ... A: Well the limit is clearly 0, which you get by substituting since cos(xy) is continuous. So now ... | |
| Can this be solved? | 10/8/2008 |
| Q: I tried every logarithm and convergence trick I know and still came up empty. Can this equation be ... A: no it can't. Consider the function: f(t)=1/t + 1/t^2 +1/t^3 + 1/t^4 +1/t^5 You are aksing if the ... | |
| quadratic funtions | 10/7/2008 |
| Q: hey there would really appreciate if you could help me out. the question is: Determine the value of ... A: The x axis is y=0. If you look at the quadratic formula you see a plus or minus the square root of ... | |
| linear transformations | 10/6/2008 |
| Q: two 2x2 matrices A= (0.5,-sqrt3/2)(sqrt3/2, 0.5) B= (1,2)(0,1) a) calculate matrix powers A^2 and ... A: The linear map given by your matrix A is just a rotation around the origin ccwise of 60 degrees. The ... | |
| Permutation of increasing numbers | 10/2/2008 |
| Q: If I have a pool of N numbers, and P positions, where P<N, how many ways can I fill the positions ... A: Well I hope I understand the question. So for you want P numbers in a row, nondecreasing and all in ... | |
| bearings and azimuths | 6/30/2008 |
| Q: good day, i am having trouble understanding the conversion of bearing to azimuth and azimuth ... A: This should be quite easy, see ... | |
| Unit Cancellation | 6/15/2008 |
| Q: Here is myFind the kilowatt-hours of electricity used by a light bulb with a rating of 75 watts if ... A: just write everything as fractions qand cancel the units if it helps you. 130 hours * 75watts ... | |
| Plane Trigonometry | 8/31/2007 |
| Q: I'm trying to solve the following problem and am not really sure how to set up the triangle. A ... A: As a hint try extending the vertical side representating the antenna down until you have a right ... | |
| Proofs | 8/29/2007 |
| Q: Can you please help me withe following: Is it True or False and prove it: 1)A+BC=(A+B)(A+C) i ... A: You are right the first equation is false. To show it's false you just need to find a single choice ... | |
| mathematics | 8/29/2007 |
| Q: x-1-2*sin(pi*x)=0 A: This equation is x=1+2sin(Pi*x) First of all notice that sin of anything is always between -1 and ... | |
| Ages | 8/6/2007 |
| Q: Hey David, this is more of a riddle than a math problem (even though it deals with math). I thought ... A: Assuming you have typed the puzzle exactly as written then your answer is wrong. According to you, ... | |
| Turn Radius | 8/6/2007 |
| Q: I have been working on a problem trying to solve the turn diameter of an aircraft in a steady state ... A: I'm not sure how much help I can be to you on this one. I'm not even sure how your equations (1) and ... | |
| How many unique combinations | 8/3/2007 |
| Q: Can you tell me how many unique combinations there are if you have 8 possible items but only 5 items ... A: The kind of thing you want to count is called a multiset. You are looking for the number of 5 ... | |
| Pre-Calc | 8/1/2007 |
| Q: An equation of the line tangent to the graph of Y=(2x+3)/(3x-2) at the point (1,5) is...? A: This doesn't look like precalc, it looks like calculus. You need to find the slope of the tangent ... | |
| algebra | 7/31/2007 |
| Q: How to solve Quadratic equation Using Factors A: If you have ax^2+bx+c=0 and you can factor it, then you can set each factor=0 and solve. This is ... | |
| differentiation problem | 7/29/2007 |
| Q: this is a first year undergraduate question from a calculus paper, just having trouble with it, any ... A: g'(t)=-2/t^3. I assume you can plug in -1, 2 and sqrt3. So let's figure out how to get g'(t) from ... | |
| maths subject | 7/16/2007 |
| Q: I am trying to find out the name of a particular mathematics subject. But I do not know what it is ... A: There's no particular name for such a branch of mathematics, indeed interesting sequences can arise ... | |
| Trigenometry proofs | 7/15/2007 |
| Q: I am having trouble proving the following identity. Any hints or ideas would be greatly ... A: I don't see what you did but you didn't do it correctly. You should get: (1+ sin/cos + cos/sin)(cos ... | |
| logarithmic and exponential variables | 7/13/2007 |
| Q: how would one solve deductively an equation in one variable where x occurs both in a logarithm and ... A: There is no good way to do this, i.e. the solution does not have an answer in closed form. To write ... | |
| Prime Numbers & Fractions | 7/10/2007 |
| Q: Can a fraction be a prime number? If not, why, and if none are prime numbers, are they considered ... A: They are rational numbers, I would not call them composite or prime. You might want to call ... | |
| Prime Numbers & Fractions | 7/10/2007 |
| Q: Can a fraction be a prime number? If not, why, and if none are prime numbers, are they considered ... A: No, "prime numbers" are a subset of 1,2,3,4,5,6,7 ... which have only 1 and themselves as factors. ... | |
| series and induction | 6/11/2007 |
| Q: I have a math portfolio due in a few days and the teacher's like this is going to be our final ... A: 1. Your answer is right, there is nothing to prove. You are just giving a formula that matches the ... | |
| Vectors | 6/6/2007 |
| Q: I was wondering if you could please tell me hoe to change point normal form of a vector into vector ... A: Vector form: (x-1,y-4,z-5)*(7,1,4)=0 the * is a dot product. This is just saying that for any ... | |
| Math | 5/14/2007 |
| Q: On Friday, February 20, 2004, the Ohio Bureau of Motor Vehicles (BMV) unveiled the new license ... A: The total number of plates is: 26*26*26*10*10*10*10 since there are 26 choices for a letter and 10 ... | |
| math/algebra | 5/13/2007 |
| Q: Hemmer. I need some help with some homework. Yes, you're going to be doing my homework...haha...if ... A: 1. THe discriminatnt is b^2-4ac which in this case is -15 so there are no real roots, two imaginarys ... | |
| Trig | 5/13/2007 |
| Q: y=Sin1/2X how do you do this and graph this A: It's just the same as the graph of y=sin x except it is stretched out in the horizontal direction. ... | |
| Gradient/intercept | 5/7/2007 |
| Q: .i wanted to check and correct if i made any mistake...or approached it wrongly. Determine the ... A: To find the y-intercepts just set x=0 and solve for y. Thus the y-intercepts are: (0,-4) and ... | |
| volume of odd shape | 5/7/2007 |
| Q: i have a object with the same shape as the top of a wine glass or a rounded off frustum. It is 8.5 ... A: Unless you have aspecific formula for the shape I cannot get the volume exactly. The volume of s ... | |
| Pre-Calc | 5/6/2007 |
| Q: I need help finding the inverse function of f(x)=square root of (x-2). Thanks A: Just interchange x and y and then solve for y. y=sqrt(x-2) x=sqrt(y-2) x^2=y-2 y=x^2-2 So the ... | |
| logarithms | 5/3/2007 |
| Q: I need help writing -2log3(1/x)+(1/3)log3(square root of x) as a single logarithm. Thanks! A: I am assuming the 3 in your problem is the base of the log so I will just write log instead of ... | |
| non-associative mathematics | 5/2/2007 |
| Q: Can you give me any examples of mathematical entities that do not obey the associative law? (A*B)*C ... A: You question is a little misphrased, it's not a question of which "entities" obey the associative ... | |
| modern geometric | 4/19/2007 |
| Q: im college student and i got question and expected will come out in exam, thank you sir.. the ... A: This will be very hard for me to answer without drawing pictures. I suggest you visit the website: ... | |
| Vector problem | 4/18/2007 |
| Q: Any chance you could show me how its done? Any help appreciated. Cheers Scott 1.Let u=2i-3j+4k, ... A: u=(2,-3,4) v=(1,-1,2) a. The cross product is perpendicular to both. In this case it is (-2, 0, 1) ... | |
| Trigonometric equation | 4/18/2007 |
| Q: The ferris wheel at an amusement park measures 100 ft in diameter. When running at full speed, the ... A: I suggest you draw a large picture of the Ferris wheel 4 feet off the ground. It has a radius of 50. ... | |
| differentiation question - calculus | 4/17/2007 |
| Q: hallo sir can you help me? im from malaysia, i got an exercise but it's too difficult to solve, so i ... A: Let x be the number of trees. The total output per tree is ... | |
| Precalc Analytic trig | 4/11/2007 |
| Q: I learn a bit differently So I will need the "why we do this" answered along with the solving of the ... A: tan3x(tanx-1)=0 When you multiply two things together and get 0 then one or the other must be zero. ... | |
| Precalc Analytic trig | 4/11/2007 |
| Q: I learn a bit differently So I will need the "why we do this" answered along with the solving of the ... A: I think you better send me the question above and be careful where your parenthesis are, because 0 ... | |
| Advanced Algebra | 4/7/2007 |
| Q: I don't know how to write out the problem out on my key board so I'am going to write it out in ... A: When you take ln of each side you will get: (2x+1)ln5=(4x-1)ln3. No just expand out and solve it ... | |
| complex numbers | 3/29/2007 |
| Q: I need to substitute z = x + yi into z^5 = 1. Then expand on left side. Then equate the real parts ... A: So do it! You know i^2=-1 so use the binomial theorem. ... | |
| re: polynomial factorisation | 3/28/2007 |
| Q: I am having trouble remembering the steps in factorising numbers/pronumerals raised to powers 3 and ... A: Factoring polynomials is not easy! One helpful fact to know is the following theorem: Theorem: ... | |
| math problem | 3/26/2007 |
| Q: is my reasoning correct? solve for x: 2^2x-3(2^x)-4=0 2^x*(2^x)-3(2^x)-4=0 2^x(2^x-3)=4 ... A: Your answer worked out but the reasoning at the very end is wrong. Just because you have ... | |
| Isomorphism | 3/13/2007 |
| Q: Can you please help me in proving the follwoing: prove that isomorphism is an equivelance realtion ... A: Suppose G is a group. The map i(g)=g is an isomorphism from G to itself so the relation is ... | |
Advanced Math
Answers by Expert:
David Hemmer
Top Expert on this page
Expertise
I can answer almost any question from undergraduate mathematics courses.
Experience
Mathematics professor.
Education/Credentials
Ph.D. University of Chicago
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