check

  1. C

    check my answer please!

    2^2 x 2^3 = 2^2+3 = 2^5 = 32
  2. M

    Eulers Method - Please Check My Work

    Hiya, Just completed this task on rulers method. Can you please check it? Question: Use Eulers method to obtain a numerical solution for: dy/dx = y/x +x^2-2 x=1, y=3 range 1.0 to 1.5 intervals of 0.1 Thank You
  3. E

    check on internal homogenity - external heterogenity

    I don't know if this is possible: i have a large set of stock data from Yahoo! i want to filter on all stocks which have risen 20% on 30 days, and compare the homogenity of the these stock features (before that period) between that dataset and its heterogenity with the other data (or eg stocks...
  4. P

    Check my work on finding sigma given percentile

    I have X, a normally distributed random variable with mean 4. If 80th percentile of X = 4.8, then sigma = ? I did .80 = (4.8-4)/sigma then solved for sigma I got sigma = 1. Just wanted someone to check since it equaling 1 doesn't make sense to me.
  5. T

    Check solution on singular matrix problem.

    I solved a problem but wasnt sure if my solution was correct. The problem is number 30 in the textbook. I am attaching the question and solution below. Does my work make sense?
  6. B

    Check these two Triple Integrals (cylindrical and spherical)

    Sphere Work (the picture I drew is an xy trace of the sphere, if that isn't clear) http://i.imgur.com/WMWUp1D.jpg?1 The sphere problem asks you to find the volume of the region bounded by the plane z=1/2 and a ball with radius 1 centered at the origin using spherical coordinates. I'm not even...
  7. O

    Can somebody check my solution: Control Theory with scrap values

    Okay, so I have been working on this problem but want to know if I am correct or on the right lines. I set up the Hamiltonian Took the derivatives with respect to u and x but I am a little unsure about what I do after the boundary conditions and if I am correct with what I did with the scrap...
  8. T

    For the system of equations check whether the 2 conditions in IMF theorem are true

    For the system of equations below, check whether the two conditions in the Implicit Function Theorem are satisfied at point A = (x, y, t) = (1, 1, 0), where x and y are variables and t is a parameter. If yes, find the expression for &dx/&dt and evaluate it at A. EQ#1 xy2 − y = 5t EQ#2...
  9. M

    Variation of Parameters work check

    Can someone check my work and see what I did wrong. This is an initial value problem. Here's the question and my answer: Here's my work. Sorry if it is hard to read.
  10. M

    Check saddle point

    Is there a way to check if a saddle point I calculated in a three variable function is OK? The function is f(x,y,z)=(x+z^2)e^(x(y^2+z^2-1)) and I got a saddle point in x=1, y=0, z=0. f(1,0,0)=1/e
  11. N

    long question , confusing , please check them for me,urgent!!!

    Same as the title, please figure out what is wrong for my working ,, questions: 1)A helicopter takes off from a point 120m away from an abserver located on the ground, and rises vertically at a constant rate of 2.5m/s.At what rate is the elvation angle of the observer's ine of sight to te...
  12. L

    Quick check - Log problem

    Review: Log problems [Ongoing] log3(y+2) = log3(y-7) + log34 log3(y+2) = log3[(4)(y-7)] y + 2 = 4y - 28 30 = 3y y = 10 Have I done this correctly?
  13. L

    How to check sum of power series?

    Hello, first post here! I have an upcoming calc exam and wanted a way to double check my answers. How can I confirm I have the correct answer for a function written as the sum of a power series (centered at 0) For example how can I confirm that f(x)=1/(2-x) is equal to the sum of (x^n)/2^(n+1)...
  14. S

    problem check

    I got a = -8, and a = 1
  15. S

    check on solving and simplifying

    for the first one i got: x = -6 for the second one i got: x^2 + 3x - 8 / (x+4)(x-3)
  16. T

    Check my proof for integral test please

    Does my proof work? The question is prove: \sum_{n=1}^{\infty}(\frac{1}{nx}) diverges for any value of x. I initially thought it diverges because the sum 1/n is divergent... but please check my proof. We know that: \sum_{n=1}^{\infty} \frac{1}{n} > M' for every n>N \sum_{n=1}^{\infty}...
  17. D

    Need you all to check and make sure I'm evaluating a function correctly.

    So my instructor stuck a couple of these questions into our exams and it says: Evaluate the function: 1) Find f(-3) when f(x) =2x^2+3x+5....Do I just need to substitute -3 for the x's and see what I get? Also, I get a couple questions that says: Use synthetic division to determine f(-4), if...
  18. A

    Calculus 1 - 3 snags (work included), could someone double check me on these?

    Hi everyone! I'm taking a Calculus course and have hit a couple snags. The following are the problems I have (first two are to be implicitly differentiated, the third differentiated normally by use of the quotient rule), followed by what I tried to solve each. If anyone could guide me so that I...
  19. T

    Can someone check my proof?

    The question is: Prove that a sequence {a_n} converges to 0 if and only if the sequence of absolute value {|a_n|} converges to 0. My Proof (which I am a bit skeptical of): We will start with the condition that: a_n \rightarrow 0 ... so |a_n - L| < \epsilon for n>N. The limit is given as 0...
  20. B

    Derivatives answer check

    Hello there I was just wondering if you guys could check my answers: 1) Let g be a function such that g(-1)=1 and -1 ≤ g'(x) ≤ 1/2 for -6 ≤ x≤ 5 and for . a. Use the RTP to find upper and lower bounds on g(3). b. Use the RTP to find upper and lower bounds on g(-4). So for (a) i got: -3≤ g(3)...