Recent content by 159753x

  1. 159753x

    Calculating voltage division for an AC circuit?

    I got it! The total voltage coming from the AC source varies with time, so the voltage across the resistor also varies with time. Once I realized that this voltage of 110V is really the length of a vector in the complex plane, it becomes much easier. Obviously, if the voltage of the resistor is...
  2. 159753x

    Calculating voltage division for an AC circuit?

    Homework Statement A series RL circuit is connected to a 110-V ac source. If the voltage across the resistor is 85 V, find the voltage across the inductor. Homework Equations V = IR The Attempt at a Solution How does one go about solving this? My intuition tells me that KVL must be...
  3. 159753x

    Simple divergence/Green's theorem question

    I think I have figured it out. If you consider the outward flux from the bottom of the hemisphere (ie. a disk), then that is equal to 9 Pi. The total flux through the curved surface is then (36 - 9) Pi, or 27 Pi
  4. 159753x

    Simple divergence/Green's theorem question

    I'm exploring the divergence theorem and Green's theorem, but I seem to be lacking some understanding. I have tried this problem several times, and I am wondering where my mistake is in this method. The problem: For one example, I am trying to find the divergence of some vector field from a...
  5. 159753x

    Easy electrical engineering question - why is my answer wrong?

    Ahhhhhhh. So the equation should really be -1 * v(x) = 2 * I because of the passive sign convention and the direction of the current. Then it becomes v(x) = -(3 + v(x)/4) * 2 v(x) = -6 + -v(x)/2 (3/2) v(x) = -6 v(x) = -12/3 = -4 V Thanks for pointing that out gneill! I understand now...
  6. 159753x

    Easy electrical engineering question - why is my answer wrong?

    Hi! This is simple mesh analysis. I wanted to try to solve the problem with nodal analysis. 1. Homework Statement Homework Equations V = IR We are supposed to use mesh analysis or node analysis. The Attempt at a Solution [/B] First step: the two current sources (independent and...
  7. 159753x

    I'm having trouble with this proof

    http://i.imgur.com/MRjOT9K.png here are the steps of the proof in detail. After the last step, I use the relation: http://i.imgur.com/kUHerIR.png to get to what I mentioned above.
  8. 159753x

    I'm having trouble with this proof

    EDIT: in the second picture, the exponentials in the denominator should both have θ.
  9. 159753x

    I'm having trouble with this proof

    Sorry for doing this, but I don't know how to input code on this site. I'll just link to pictures. Starting with the cosine series, I am able to use this relation: http://i.imgur.com/kUHerIR.png to get this: http://i.imgur.com/PClCbED.png. After simplifying I get the following, which I am...
  10. 159753x

    I'm having trouble with this proof

    Thanks to all for the response. I ended up taking the exponential series and dividing it into two parts. One corresponds to e^+iθ and the other corresponds to e^-iθ. I can then easily take these and use the geometric progression formula. At the end of the day, I get REALLY close... I end up...
  11. 159753x

    I'm having trouble with this proof

    I'm having trouble completing this proof for homework. 1. Homework Statement Prove that cos θ + cos 3θ + cos 5θ + ... + cos (2n-1)θ = (sin 2nθ)/(2 sin θ). Prove that sin θ + sin 3θ + sin 5θ + ... + sin (2n-1)θ = (sin nθ)^2/(sin θ). Use Euler's formula and the geometric progression formula...
  12. 159753x

    Solving Complex Equations: How Can We Separate Real and Imaginary Components?

    Thanks to both of you, Mr Anchovy and Ray Vickson. I was able to solve both A and B. It is now clear to me that 2ixy = 2ixy (ie. z= -z) only when either x or y (or both) = 0. This is obvious now! :smile: The same is true for B. That was a silly oversight. I ended up with the correct...
  13. 159753x

    Solving Complex Equations: How Can We Separate Real and Imaginary Components?

    I have a few complex equations that I am having trouble solving for homework. Homework Statement Solve for all possible values of the real numbers x and y. A. (x+iy)2 = (x-iy)2 B. (x + iy + 2 + 3i)/(2x + 2iy - 3) = i + 2 C. Abs[1 - (x + iy)] = x + iyHomework Equations The example problem...
  14. 159753x

    Intuition for imaginary part of Fourier Transformation?

    Wow, that was a terrific explanation. You should consider becoming a teacher! I believe I have a better understanding now, thanks friend!
  15. 159753x

    Intuition for imaginary part of Fourier Transformation?

    Hi there, I'm having trouble understanding the Fourier transform of a function where the result in the frequency domain has imaginary components. For example, if you take the Fourier transform of Sin[t] , the result is I Sqrt[\[Pi]/2] DiracDelta[-1 + \[Omega]] - I Sqrt[\[Pi]/2]...
Back
Top