1. M

    Combining Phasors (Wave Forms)

    The instantaneous values of two alternating voltages are given by: v1= 150sin(ωt+ π/3) Volt v2= 90sin(ωt- π/6) Volts Derive a sinusoidal expression-resultant v1+ v2 in form Rsin(ωt+ α) Combine the phasors (Vectors) of each wave form? Thanks in advance
  2. Bernhard

    First Approach To Differential Forms

    What text (or chapter or section of a text) would Math Help Forum members regard as the best first introduction to differential forms?
  3. Bernhard

    Simple/Basic Example on Wedge Products of Diffferential Forms - O'Neill Section 1.6

    I am reading Barrett O'Neil's book: Elementary Differential Geometry ... I need help with fully understanding the example on wedge products of differential forms in O'Neill's text on page 31 in Section 1.6 .. The example reads as follows: I do not follow the computations in this...
  4. C

    other forms of non-linear regression equations

    Hello , I have 4 predictor variables X1,X2,X3,X4 and one response variable Y . I need some non-linear regression equations for these variables . For example one of these equations is : Y=a1.(X1^a2).(X2^a3).(X3^a4).(X4^a5) I looking for other forms ........... Thanks
  5. M

    Primality and Compositeness Criteria for Numbers of Special Forms

    Primality and compositeness testing in polynomial time .
  6. D

    logical equivalences and valid argument forms

    1. Use laws of equivalences to simplify (p\rightarrow r) \leftrightarrow (q \rightarrow r). I stopped at \sim((\sim p \cup r) \cap (q \cap \sim r)) \cap ((\sim p \cup r) \cup (q \cap \sim r)). Not sure how to simplify this. 2. Determine the validity of the argument by using valid argument forms...
  7. M

    Jordan Normal Forms

    I am trying to revise for a test and i cannot get this question. And i have know idea where to start. Question Find the JNF for the matrix of the linear transformation T: P2 --> P2 given by T(p(x)) = p(x+1) Thankss any help is appreciated. I not great at JNF
  8. M

    General tools to evaluate closed forms of series

    Hello, this is my first post on MHF. I was wondering if someone might be able to provide a general set of machinery and tools to evaluate various series (supposing they converge) into their closed form. I know this might not be able to be done for every infinite series. Sum of the tools I know...
  9. M

    Metrics close implies volume forms close

    Let g be a metric on the S^2 which is close to the standard metric \gamma, i.e. \sup_{\theta \in S^2}\vert g - \gamma \vert \leq \varepsilon for some \varepsilon small, where \vert \cdot \vert is the norm with respect to \gamma (say). Is there an easy way of showing that the volume forms are...
  10. S

    Find the minimum cost Sum Of Prods and Product of Sum forms for the function

    Find the minimum-cost Sum of Products and Product of Sums forms for the function: f(x1,x2,x3( = \summ(1,2,3,5) I know how to get the truth table etc. But they want me to use a karnaugh map to get the answer. How?
  11. bkarpuz

    ODEs, Adjoint forms and matrix representation

    Hi MHF members, I was looking up in the books I have but I could not go anywhere. Consider the higher-order ode L[y]:=y^{(n)}+\sum_{k=0}^{n-1}p_{n-k}y^{(k)}=0, which has the matrix form \pmb{Y}^{\prime}+\pmb{A}\pmb{Y}=\pmb{0}, where \pmb{Y}=\left( \begin{array}{c} y \\ y^{\prime} \\ \vdots \\...
  12. K

    Solution forms for the CFs of 2nd order differential equations: how are they derived?

    I'm currently in year 12 studing FP2 maths and we've just finished second order differential equations. One of the things that bugs me about Edexcel is their lack of proof (I know some things are out of spec, but a pointer to a site or something would be good); more particularly, for the...
  13. C

    Row echelon forms

    If A is a 3 x 5 matrix, then the number of leading 1's in any of its row echelon forms is at most _____________?
  14. G

    Definition quadratic forms over a module

    I have a question about the following definition from my book: My questions are the following: When I looked up the definition of a quadratic form over a field property I saw that (1) is sufficient. Why should property (2) in this case also be included in the definition? Can anyone give an...
  15. A

    Isotropic forms in field of p-adic numbers

    Hi, for which primes p are the quadratic forms 7x^2-y^2-5z^2 and w^2+x^2+3y^2+11z^2 isotropic over the field over p-adic numbers \mathbb Q_p ? A abbreviated form for the two quadratic forms above is \left \langle 7,-1,5 \right \rangle and \left \langle 1,1,3,11 \right \rangle. Define...
  16. ModusPonens

    Volume forms

    Hello I need help understanding something. A volume form is defined as being a non vanishing form in a manifold M. But I'm missing something here. Does it mean that the multilinear function is not null, does it mean that the coordinate functions never vanish or does it mean that the value of...
  17. D

    Help with fundamental forms please?

    I am having trouble with these problems, please help me with them if you can and explain your work along the way. Much appreciation. Hw 8 problem | Flickr - Photo Sharing! This one deals with coformal fundamental forms, and proving that they must have a certain relationship for the surface to...
  18. C

    Steps between 2 forms of divisons

    Hello! (((l+1)^2)/((2l+1)*(2l+3))) + ((l*(l+1))/(2*(2l+1))) - Wolfram|Alpha I can't solve, how to get the Alternate form from the Input one on the link. Please somebody help me, step-by step to understand, how do the calculator did it. Thanks :)
  19. A

    Abstraction and Indeterminate Forms of Limits

    \lim_{x\to 0} \frac{2x^2-3x-4}{x^2-1} I had this problem on a quiz today and I don't feel comfortable with how I approached it. Since the highest degree of both the variables in the numerator and denominator are the same, I assumed that the limit as x approaches zero would be the quotient of...
  20. T

    rectangular and polar forms

    z1 = 2 + j2 z2 = 1 + j5 z3 = j6 what is Y when : Y = (1/z1) + (1/z2) + (1/z3) 1/z3 how is that done??????