# Search results

1. ### Engineering Analysis of a Digital Circuit

Homework Statement 1. (a) Remove all the internal bubbles in the circuit by applying DeMorgan's theorem so that the circuit consists of only AND gates and OR gates, and INVERTERS. INVERTERS can only be used for the inversion of inputs. Note that there is a 3-input NAND gate shared by both F1...
2. ### Electric Potential and a Conductor

Hmm interesting. I've got it now. The electric potential inside the shell is the sum of the electric potential on the outer edge and the inner edge. This yields: V=k\frac{3Q}{4r_1} Ok, but I'm still confused on the next question. I would think the electric potential inside the cavity would...
3. ### Electric Potential and a Conductor

Never mind, what that tells me is that the electric potential inside the conductor is constant, but how do I derive the value?
4. ### Electric Potential and a Conductor

Yes, I know that vec(E)=-vec(\nabla V) I also know that E=-\frac{dV}{ds} when ds||E If I use the second equation I set E equal to zero and you have v=0 which is wrong. The first one I'm not even sure how to use since I have magnitudes of vectors not vectors.
5. ### Electric Potential and a Conductor

Homework Statement A hollow spherical conductor, carrying a net charge +Q, has inner radius r1 and outer r2=2r1 radius (see the figure ). At the center of the sphere is a point charge +Q/2. A.Write the electric field strength E in all three regions as a function of r: for r>r2,r1<r<r2...
6. ### First Order Linear DE System

thanks, I figured it out
7. ### First Order Linear DE System

Homework Statement I need to solve this DE system for a lab: q_1'=2-\frac{6}{5}q_1+q_2 q_2'=3+\frac{3}{5}q_1-\frac{3}{2}q_2 Homework Equations The Attempt at a Solution I know how to use the method of elimination to solve such systems, but this is non homogeneous because of the added...
8. ### Jacobian Change of Variables Question

you can rewrite the exponents as (x-y)(x+y). Using the substitution u=x-y and y=x+y you have a parallelogram with bounds v=3u,v=3u-8,v=-2u+1,v=-2u+8. Therefore, the area can be represented by the following integrals...
9. ### Jacobian Change of Variables Question

Homework Statement Evaulate the integral making an appropriate change of variables. \int\int_R(x+y)e^{x^2-y^2}dA where R is the parallelogram enclosed by the lines x-2y=0, x-2y=4, 3x-y=1, 3x-y=8 . Homework Equations The Attempt at a Solution I'm not sure what change of variables I should...
10. ### Spherical Coordinates Integral

Hmm, that's what I thought you were thinking. I handed in the assignment today and got the answer key. They setup the integral the way you did in the answer key. However, I would argue that part of the region in that integral is not under the cone. Everything under the cone is contained within a...
11. ### Spherical Coordinates Integral

Ok, I think I was misinterperting the volume described. I took it to mean basically the shadow cast down by the cone on the xy-plane, since that region lies under the cone, above the xy-plane, and in the sphere. I'm not sure if the area you are thinking of is correct though. In the area you are...
12. ### Spherical Coordinates Integral

Oh, haha. Cant believe I forgot that. I would think the upper limit on rho depends on phi because with this shape, you can change theta all you want and rho is not going to change. However, changing phi changes rho, this is because the solid is symmetrical about the z-axis. Right?
13. ### Spherical Coordinates Integral

Homework Statement Using spherical coordinates, find the volume of the solid that lies within the sphere x2+y2+z2=4, above the xy-plane and below the cone z=√(x2+y2) Homework Equations The Attempt at a Solution This is what I have so far...
14. ### Polar Coordinates Improper Integral Proofs

update, I proved everything, however I'm not sure If my proof for b is what they're asking for. I said that \int_{-\infty}^{\infty}e^{-x^2}dx\int_{-\infty}^{\infty}e^{-y^2}dy=\int_{-\infty}^{\infty}\int_{-\infty}^{\infty}e^{-(x^2+y^2)}dy dx and since I had proved that the rhs of the...
15. ### Polar Coordinates Improper Integral Proofs

Homework Statement (a) we define the improper integral (over the entire plane R2) I=\int\int_{R^2}e^{-(x^2+y^2)}dA=\int_{-\infty}^{\infty}\int_{-\infty}^{\infty}e^{-(x^2+y^2)}dy dx=\lim_{a\rightarrow\infty}\int\int_{D_{a}} e^{-(x^2+y^2)} dA where Da is the disk with radius a and center the...
16. ### Curvature Proof

Homework Statement show that the curvature of a plane curve is \kappa=|\frac{d\phi}{ds}| where phi is the angle between T and i; that is, phi is the inclination of the tangent line. Homework Equations The Attempt at a Solution I'm not sure how to start this one out. Any ideas?
17. ### Vector Application Problem

Oh wait. you know v(0)=0. So this could be arranged to be m(t)\frac{1}{e^2}=m(0) so it uses 1/e2 of it's fuel. Is this what you were thinking?
18. ### Vector Application Problem

Homework Statement A rocket burning it's onboard fuel while moving through space has a velocity v(t) and mass m(t) at time t. If the exhaust gasses escape with velocity ve relative to the rocket , it can be deduced from Newton's Second Law of Motion that...
19. ### Proof of r(t) and r'(t) orthogonal on a sphere

Ok, I stared at the problem for a good amount of time and I think I have it. I managed to manipulate a few things... 2( \vec{r}(t) \cdot \vec{r}'(t))=\frac{d}{dt}(\vec{r}(t)\cdot\vec{r}(t))=\frac{d}{dt}(\left\|\vec{r}(t)\right\|^2)=0 so it must be true then that also...
20. ### Proof of r(t) and r'(t) orthogonal on a sphere

Hmm. Lineintegral1: Ok, I can rewrite what I have written. \vec{r}(t) \cdot \vec{r}'(t)=0 \left\|\vec{r}(t) \right\|\left\|\vec{r}'(t)\right\|cos\theta=0 ||r(t)|| has to equal the radius of the sphere. However, isen't that what I'm suppose to be proving given that r(t) and r'(t) are...
21. ### Proof of r(t) and r'(t) orthogonal on a sphere

Homework Statement if a curve has the property that the position vector r(t) is always perpendicular to the tangent vector r'(t). show that the curve lies on a sphere with center the origin. Homework Equations The Attempt at a Solution I'm not quite sure how to prove this. I...
22. ### Surface with specifications

Thanks. You wind up with the cone 4y^2+4z^2=x^2
23. ### Surface with specifications

Homework Statement Find an equation for the surface consisting of all points p for which the distance from P to the x-axis is twice the distance from P to the yz-plane. Identify the surface. Homework Equations The Attempt at a Solution...
24. ### Vector Proof

Can anyone help me?
25. ### 3 Orthogonal Vectors Problem

Yes, but since the vectors have to be unit vectors and both vectors a and c are orthogonal to b, |v| is going to be the same regardless. You can rotate a vector by a specific angle and the others have to stay orthogonal so they will move as well by the angle maintaining |v|. That's why I chose...
26. ### 3 Orthogonal Vectors Problem

Homework Statement A. Given unit vectors a, b, c in the x, y-plane such that a · b = b · c = 0, let v = a + b + c; what are the possible values of |v|? B. Repeat, except a, b, and c are unit vectors in 3-space Homework Equations The Attempt at a Solution I have solutions for both that I'm...
27. ### Vector Proof

I can replace the c\bulletb side with what you've suggested but then how am I supposed to include that it is twice the angle. I loose this ability without the trigonometric function.
28. ### Vector Proof

I'm not quite sure what you are suggesting. I can draw the relationship |a||b|cos \theta = |c||b| cos 2\theta I can eliminate the |b| from both sides, but I don't know where to go from there, since |c| doesn't seem to help when substituting.
29. ### Drawing a Collection Of vectors Satisfying Cross Products

Homework Statement Given a = <1,2,3> and b = <1,-1,-1>, sketch the collection of all position vectors c satisfying a x b = a x c Homework Equations The Attempt at a Solution I've calculated a x b = <1,4,-3> and Defining c = <x,y,z> I found a x c = <2z-3y, z-3x, y-2x>. I want to...
30. ### Vector Proof

Homework Statement If c=|a|b+|b|a where a,b, and c are all non zero vectors, show that c bisects the angle between a and b Homework Equations The Attempt at a Solution I'm taking the approach to prove that the angle between b and c= the angle between c and a I have written...