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Advanced Math/Questions Answered by Expert Jack Cheng
| Subject | Date Asked |
| Best Base? | 4/9/2007 |
| Q: This is kind of a bizarre question, but I'd like to know if ten really is the optimal increment for ... A: I think it comes more down to tradition than what is optimal. We are so used to the number 10 that ... | |
| answer me soon | 4/7/2007 |
| Q: In a survey of 60 people, it was found that 8 read only News (N) 12 read only Dawn (D) 10 read ... A: I found that drawing a Venn diagram is very helpful in solving problems like this: The only numbers ... | |
| probability | 2/19/2007 |
| Q: There are 9 married couples attending a party where two door prizes (the prizes are the same) are ... A: What is the probability a married couple wins the prizes? I think it's 1/17. The first win can be ... | |
| data | 2/17/2007 |
| Q: Jack, I've just had a go at the trendline, i know now how to make one, however, how do i make up the ... A: I guess I was really lucky when I did the examples, picking the easiest two to do. ;) The other ... | |
| data | 2/14/2007 |
| Q: heres a link for you to download the data i am using. what i need to do is extrpolate data so to ... A: Using regressions would probably be your best bet. Using your data, you can create a scatterplot. ... | |
| Right triangles and square roots | 2/5/2007 |
| Q: I am having such a hard time with these. I do not have a clue on how to do this, I am online ... A: Sorry about the delayed reply. 1) What is the angle for an equilateral triangle? You now have an ... | |
| math | 1/7/2007 |
| Q: What is the function rule if the input numbers are 1,2,3,4 and the output numbers are 3,8,13,18? A: Notice that the difference between consecutive numbers is constant: 5. That means the function is ... | |
| Limits | 1/5/2007 |
| Q: im having a little trouble finding the limit of this sequence: root(2), root(2*root(2)), ... A: Each number gives you one hint, and each hints gives you more information to help you solve the ... | |
| trig | 1/2/2007 |
| Q: Please help me!! X is between 0 degrees and 360 degrees (meaning show answer in degrees??) 3sin(x ... A: I don't have a calculator, so I can't finish the problem for you. But here it is: sin(x+20)= -1/3 ... | |
| Pre calc trig Review | 1/1/2007 |
| Q: Sorry, but I have one last question. I asked this question to both experts Jack Cheng and Sherman D ... A: They (We) are both right. I just left mine as [sqrt(3)+1] / [1-sqrt(3)] while Sherman multiplied ... | |
| Pre Calculus Trig. Review | 1/1/2007 |
| Q: I had a long trig review packet to do over Christmas break. I have completed most of the questions ... A: 1) Correct! 2) It can't be right. Do it on a calculator; they don't even come close. I got ... | |
| Pre Calculus Trig. Solving Equations | 1/1/2007 |
| Q: SOLVE for X in each of the following: a) X is between 0 and 2pi (meaning show answer in radians??) ... A: a) you're probably right in that it's looking for an answer in radians. Your answer is a bit off ... | |
| Pre-Calc: Trigonometry | 12/31/2006 |
| Q: Please help me!! a) simplify completely: tanx + cotx / csc^2 x b)simplify completely: sin(pi + x) ... A: The first one is absolutely correct :) The second one is a little bit off. When you subtracted, you ... | |
| Spherical Geometry | 12/29/2006 |
| Q: I am trying to help a co-worker with some math problems that her 9th grade daughter did not ... A: I am really impressed the your co-worker's daughter is learning spherical geometry in 9th grade. ... | |
| gas vlume | 12/22/2006 |
| Q: I am trying to figure out how to deal with methane gas created by cattle, which apparently is a ... A: 500 liters is a measurement of volume :) 1 L = 1000 mL = 1000 cm^3. 500 L = 500,000 mL = 500,000 ... | |
| m.p.h | 12/21/2006 |
| Q: my car does 7.9kilomiter for every100lts how many miles pergallon is this than you A: Let's solve this with dimensional analysis. 1 km = 0.62 miles 1 L = 0.26 gallons (7.9 km)/(100 L) ... | |
| compound interest | 12/20/2006 |
| Q: I think this fits your expertise, but please excuse me if I'm in the wrong forum. I'm not a student ... A: I want to make sure that it's okay if I assume some things in your problem: 1) Interest ... | |
| equations | 12/18/2006 |
| Q: 1) Sqrt(x+1) = 1 2) Sqrt (x^2+4) = 2 Sqrt(2) 3) 3/x = 2/(x-1) - 2/(x^2-x) A: 1) sqrt(x+1) = 1 sqrt(x+1)^2 = 1^2 x+1 = 1 x= 1-1 = 0 2) sqrt(x^2+4) = 2 sqrt(2) ... | |
| linearization | 12/16/2006 |
| Q: how can we use linearization to find an approximation to sin 31 . could you plz tell me ? A: Nabil, I am assuming you probably know how to do linearization. But man, this question just doesn't ... | |
| triangle | 12/15/2006 |
| Q: arrange the numbers 1 through 15, placing them in boxes so that the two numbers in any adjacent box ... A: Perhaps I am misunderstanding the question, but if the boxes are in a single row, and you have the ... | |
| SQUARE FEET IN A PIE SHAPE AREA> | 12/15/2006 |
| Q: HOW CAN I FIND THE EXACT AREA OF A SHAPE WHEN IT HAS NO EQUAL SIDE'S ? FOR EXAMPLE THIS SHAPE HAS 3 ... A: There is a formula called the Heron Formula that gives you the area of a triangle based on the three ... | |
| please help | 12/15/2006 |
| Q: f (x) = x^2 - 2x + 3 / x - 2 , Df = R1 {2} a) find eventual virtual zeros b) find eventual ... A: I am not familiar with some of the terms and symbols you are using, like eventual asymptotes, ... | |
| algebra 1 | 12/14/2006 |
| Q: can you multiply polinomilas A: Absolutely! In math, anything can be done. As an example, (2x+2) * (3x+3) = 6x^2 + 12x + 6 You ... | |
| interest | 12/14/2006 |
| Q: A total of $12,000 is invested in two corporate bonds that pay 7.5% and 9% simple interest. The ... A: I am assuming that the investor wants EXACTLY $990 of income. Otherwise, just make the investment ... | |
| Calculus help | 12/12/2006 |
| Q: Hey can you help me with these 2 questions i can't figure out i hosted an image of the questions ... A: 1) It's a product rule and chain rule problem. y = e^(-2x)*sec(3x) y' = [(dy/dx) e^(-2x)] * sec(3x) ... | |
| Marble Probability | 12/11/2006 |
| Q: A jar contains 7 red , 5 blue , 3 green , and 3 white marbles.4 marbles are drawn without ... A: Probability is expected/possible. Possible is 7+5+3+3 = 18. a. one marble all red: 7/18 two ... | |
| trig with out a calculator | 12/10/2006 |
| Q: an engineer needs to run a taught cable from the top of a tall building to a small post 30m away ... A: You basically need the cos 75*. Unless I am mistaking it for something else, to use the slide ... | |
| word problem | 12/8/2006 |
| Q: A small company that manufactures snowboards uses the relation P=-81X sqaured + 162x to model its ... A: To find the maximum profit, you take the derivative of the equation and find its x-intercept. That ... | |
| pre cal | 12/6/2006 |
| Q: find all solutions of the eqaution in the interval [0, 2 pie] sqaure root of 3 tan 3x=0 A: Sqrt(3 tan 3x) = 0 3 tan 3x = 0 tan 3x = 0 The tangent function is only zero when the ... | |
| Application of L' Hospital's Rule | 12/6/2006 |
| Q: In my mathbook this section deals with L'Hospital's Rule but I can't figure out how to use it here. ... A: I got this question from the Question Pool, so it might be a bit late. Just calculating the limit ... | |
| sequences | 12/5/2006 |
| Q: how do you do this question? 'Consider the geometric sequence t1,t2,t3,t4,... Show that ... A: The answer to this question lies in the logarithm properties that log(a*b) = log(a) + log(b) and ... | |
| Help with Math Proofs | 12/5/2006 |
| Q: I am having some problem with a couple of math proofs, and I hope you can help. On each proof, I ... A: 1) The only way a division can be zero is if the numerator is zero, but it's one. So the division is ... | |
| horizontal asympototes | 12/4/2006 |
| Q: how do you solve for horizontal asympototes? I know for vertical you set denominator to zero and ... A: The horizontal is similarly easy. Just take the limit as x approaches infinity. If it is a number ... | |
| trig help | 12/3/2006 |
| Q: how do you simplify sin/cos+cos/sin identity? A: First, it needs to be sin x and cos x (just sin and cos is meaningless). I almost failed a trig test ... | |
| algebra ii | 12/3/2006 |
| Q: regarding the question on 11/14/06 about the pre-calculus problem, how would you find the domain of ... A: I am assuming you mean this"The water in a cylindrical tank 4ft in diameter empties through a hole ... | |
| Help with Math Proofs | 12/3/2006 |
| Q: I am having problems with a couple of math proofs, and I was hoping you could help? Proofs are not ... A: Proofs aren't my favorites either (except mathematical induction), but we go: 1) (-a) * b = -(a*b) ... | |
| Math | 12/2/2006 |
| Q: Can you help me with the following math questions: What is the product of 7/16, 4/3 and 1/2? The ... A: Multiplication of fraction is very simple. All you have to do is treat the numerator and ... | |
| Calc problem | 12/1/2006 |
| Q: I was wondering if you could help me with this problem please. ... A: I am assuming you mean the sum of sqrt(n)/log n from n=2 to infinity, and log is the natural log. ... | |
| Integration | 12/1/2006 |
| Q: Can you help me with this problem. Integrate |xarcsin(-a/x)dx. Thank you, Kathrine A: Sorry about the delay, I was out for the weekend. Here are my hints on solving this: Use ... | |
| Crank angle to piston hieght | 12/1/2006 |
| Q: Im wanting to know how to calculate the varied piston hieght of an engine in relation to crankshaft ... A: I am not very familiar with cars, but here's my try. From your description, I am assuming a rod on ... | |
| conversion using dimensional analysis | 11/30/2006 |
| Q: Please help walk me thru the process of converting units of measurement. I need to convert 100 yards ... A: I am not sure which way you are doing it, but here's how I do it: 100 yards * (3 ft / yard) = 300 ... | |
| Pre calc | 11/29/2006 |
| Q: construct a box from 8x8 piece of cardstock with largest volume A: I would have to do optimization (Calculus) to solve this problem. And since the subject is pre-calc, ... | |
| Word problem | 11/29/2006 |
| Q: One half the members of a junior math team are 9th graders. One fourth of the remaining members are ... A: Let x be the number of members on the team. Here's what I derived from what you gave me. [VIEW ... | |
| trigonometry help | 11/28/2006 |
| Q: can you help me i don't have a TI89 calculator 1). Find the value of: a. log sin 62°22'33" ... A: Sorry that I took so long. I was out for a while. You don't need a graphing calculator for this, ... | |
| half lifes and exponential decay | 11/28/2006 |
| Q: Durring an economic recession, the number (N) of active stock market traders at time (t) after the ... A: Sorry about the delay; I was out for a while. N = 1/2 N. (I used N. instead of No because o ... | |
| Pre Calc | 11/28/2006 |
| Q: Find a simplified formula for the expression (a) sin (3x) in terms of sin(x) (b) cos (3x) in terms ... A: The answers are the same. 3 sin x cos^2 x - sin^3 x = 3 sin x (1 - sin^2 x) - sin^3 x = 3 sin x ... | |
| intermediate algebra | 11/28/2006 |
| Q: Can you assist with the following? Simplify by factoring. Assume that all expressions under ... A: Here's a hint for next time: square roots can be represented as (x)^(1/2). So the square root of 9 ... | |
| help | 11/27/2006 |
| Q: if you take infinity away from infinity, do you still have infinity left. (infinity - infinity = ?) A: That's very philosophical question. First, you cannot even do the subtraction of infinity - ... | |
| trig | 11/26/2006 |
| Q: how do you find sector area in a circle. I know there's a formula but I totally forgot it. And how ... A: I misunderstood your question at first when you asked "sin square (pie over 2 -x) + sin square x". ... | |
| help | 11/26/2006 |
| Q: Find a simplified formula for the expression (a) sin (3x) in terms of sin(x) (b) cos (3x) in terms ... A: For these two problems, you have to use the trig formulas: sin (A+B) = sin A cos B + sin B cos A ... | |
| Circles | 11/23/2006 |
| Q: i couldn't find anyone else that could answer this: "this question has been denied by other ... A: I would hate to reject your question given what you've been through, but frankly, this question is ... | |
| HELP... | 11/20/2006 |
| Q: I have a guestion. Maybe you could help me? I will appreciate.Thank You 1) Find the principal root ... A: Well, to do this, you first have to separate it into: (-1)^(1/6) * (64)^(1/6) = 2*(-1)^(1/6). Now, ... | |
| Please... | 11/19/2006 |
| Q: I have two question.Maybe you could help me? I will appreciate your help. 1)Find the rectangular ... A: 1) To get the rectangular equation, you have to eliminate the parameter. The easiest is probably to ... | |
| Shaded region/probability | 11/19/2006 |
| Q: (A square dart board) The side of the dartboard measures 30 inches. The square shaded region at the ... A: Probability is expected/possible. You can just use area as the unit of measurment. So the expected ... | |
| Mixing Problem | 11/17/2006 |
| Q: Consider a pond that has an initial volume of 10000 cubic meters. Suppose that at time t=0, the ... A: I am assuming you want the concentration of the salt in the water, as to just amount of salt. Let's ... | |
| a word question that sounds very, very difficult | 11/17/2006 |
| Q: I am a pastor working on a sermon for tomorrow (Friday). As an illustration I need a word problem ... A: Lambert, I hope this is not too late. I just got it this morning. Here's the best I can come up ... | |
| calculus | 11/16/2006 |
| Q: can you help me with this problem: A yam is put in a hot oven, mantained at a constant 200 C. ... A: Carlos, I asked your question to another expert here (Sherman D.), and here's his response: T(t) = ... | |
| application of geometry to quadratic equations | 11/16/2006 |
| Q: the altitude to the hypotenuse of a right triangle measures 12inches. if the entire hypotenuse ... A: I might not be understanding your question right. By altitude, I am assuming a line drawn ... | |
| Graphing Quadratic Functions | 11/15/2006 |
| Q: How do I draw a rough sketch of this quadratic function? Also, I need to label the vertex and the x ... A: To graph this function, let's first get a faint idea as to what it looks like first. 1) The ... | |
| Please... | 11/15/2006 |
| Q: I have two question maybe you can help me? 1) Write the polar equation of angle 45 degrees in ... A: 1) I am not very familiar with polar equations, but here's my three cents: tan 45 = y/x (in ... | |
| pre-calculus | 11/14/2006 |
| Q: Rectangle ABCD has two vertices on the semicircle y= the square root of 16-x^2 and two vertices on ... A: Nikki, It really helps to draw a picture for this question. The area of a rectangle is l*w, where ... | |
| pre-calculus | 11/14/2006 |
| Q: The water in a cylindrical tank 4ft in diameter empties through a hole in the bottom. Assuming that ... A: There are two steps to this problem. First, you have to find the relationship between the depth of ... | |
| Hard Maths Question | 11/14/2006 |
| Q: I am having alot of problems with this question and I would be very grateful if you could help. It ... A: For this question, you have understand the relationship among distance, velocity, and acceleration. ... | |
| Probability | 11/13/2006 |
| Q: How many arrangements can be made of letters in the word TROTTING? A: Hassan, I thought I sent this response already, but Allexperts.com says otherwise. So here it is ... | |
| Probability | 11/13/2006 |
| Q: Two balls are taken out at random from a bag containing 6 red and 2 blue balls. Find the probability ... A: Probability is a ratio of expected over total possible. In your problem, the total possible is 6+2 ... | |
| Probability | 11/13/2006 |
| Q: A fair die and coin are tossed once. What is the probability of a head on the coin and an even ... A: Hassan, This is actually two probability problems, one for the coin and one for the die. When you ... | |
| Calc? | 11/13/2006 |
| Q: lim as x goes to 0 of (1-cosx)/(2sin^2x)? thanks! A: I am assuming you are asking for the algebraic way to solve this (there is a way called L'Hopital's ... | |
| calculators | 11/13/2006 |
| Q: My daughter will be majoring in math in college. They are suggesting the ti-89 or the ti voyage ... A: I thinkt the TI-89 would suffice. I use a TI-83 (much older than the TI-89), and it's more than ... | |
| Calc Question | 11/12/2006 |
| Q: I was hoping you could get me started on thisA hole is cut through the center of a sphere of radius ... A: I am assuming that this is an integration problem (I can't think of any other way to do it). First, ... | |
| finite math/probability question | 11/12/2006 |
| Q: I have the following question. I have most sections of theMrs. Smith has 3 children who are part of ... A: You wrote: Hi, I have the following question. I have most sections of theMrs. Smith has 3 children ... | |
| math | 11/12/2006 |
| Q: . im in the 12th grade and my math skills is below average. i have trouble solving grade 10 math and ... A: There is no quick and fast way to master Math (sorry, but that's the truth). I am sure, though, with ... | |
| the Salami Curve | 11/11/2006 |
| Q: I am a calculus student at the University of Denver, and I have just been assigned a little project ... A: I REALLY liked it. Here are my hints on how to solve it: 1) Draw a picture of the situation. It ... | |
| lottery | 11/11/2006 |
| Q: how many different combinations are there to match every available outcome on the euro millions? ... A: I am not very familiar with the Euro Millions, like how many number there are, or how many numbers ... | |
| Distance and Miles | 11/9/2006 |
| Q: I need to find the answer to (41.4 miles) divided by (30 mph) When i work it out I always get the ... A: Your answer is correct. It's your interpretation that is wrong. 1.38 hours does not mean 1 hour and ... | |
| Polinomials | 11/9/2006 |
| Q: What is the relevance of the order of operations in simplifying a polynomial? A: This seems like a very broad question, and I am not sure if you are looking for something more ... | |
| Logrithmic differentian | 11/8/2006 |
| Q: Hope you can give me some insight to this question. Find dy/dx if y=(sin x)^x Thank you. A: For this problem, you have to do a little trick: (sin x)^x = e^(ln (sin x)^x) The e^ and ln cancel ... | |
| equation | 11/6/2006 |
| Q: for all values of x x2 + 6x + 4 = (4 + p)2 + q find the values of p and q thanks a lot, mate A: By your question, I am assuming you mean: x^2 + 6x + 4 = (4+p)^2 + q, where the ^2 means squared. ... | |
Advanced Math
Answers by Expert:
Jack Cheng
Top Expert on this page
Expertise
I can answer most questions in Math up to single-variable Calculus, including infinite series. I like to think very much, so questions with a lot of twists and turns are highly welcomed! Mathematical questions related to computer science are also highly welcomed! I can also answer some basic questions in discrete mathematics (logics, sets, some algorithms, basic number theory). I am also studying physics (mechanics in particluar), so I am willing to answer some questions relating to it.
Experience
Majoring in Mathematics.
Education/Credentials
I am sophomore/junior status in college working towards bachelor's degrees in Computer Science and Mathematics.
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