Recent content by Learner123

1. Homework about a simple inverting amplifier

Homework Statement The picture is an closed loop amplifier, the question is simple: find the closed-loop voltage amplifier of the circuit Homework Equations Av = v0/v in = - (R2/R1) The Attempt at a Solution If R2 is just simply a bunch of resistors connecting crazily, then...
2. Help me with Surface intergral!

the problem is given exactly above, nothin say about first obtant (i also thought about 1st obtant, too when i read the word "portion of", but it seems not that) so i guess the intergral is infinite is right, maybe the instructor gave the wrong problem. I wasn't sure so i asked, thank you for...
3. Help me with Surface intergral!

Homework Statement Evaluate \int\int (x^2 +4y + z)dS where S is the portion of the plane 3y +2z = 6 with 0<x<3 Homework Equations choosing x, y as variables dS = \sqrt{}(partial dz/dx)^2 + (partial dz/dy)^2 +1 The Attempt at a Solution If i choose x, y as variables or x, z as variables...
4. Intergral problem! !

got it! i didn't know that after spending 3 calculus classes, what a shame of me! thank you so much for your help and your time.
5. Intergral problem! !

I tried to do part and this is how i done (for the first intergral): u = x, du = dx, v = 1/2e^(2x), dv = e^(2x)dx uv - \int vdu 1/2xe^(2x) - \int 1/2e^(2x)dx 1/2xe^(2x) - 1/4(e^2 -1 ) x runs from 0 to 1, but 1/2xe^(2x) is not in the intergral part, so how to eliminate x? very...
6. Intergral problem! !

the first one xe^(2x) thing i guess it's intergral by part, but not sure
7. Intergral problem! !

Intergral problem! plz help! Homework Statement \oint(x: 0 to 1)\oint(y: \sqrt{}(1 - x^2) to e\overline{}x) xydydx The region bounded by y = e\overline{}x, y = \sqrt{}(1 - x^2), and x =1 3. The Attempt at a Solution i got stuck when i came to the part: 1/2 \oint(x: 0 to 1)...
8. What is speed of o-ray and e-ray and how to obtained?

i mean the formula to calculate it, any formula with any values (such as wavelength, h, c, m, T, f.....).
9. What is speed of o-ray and e-ray and how to obtained?

what is speed of o-ray and e-ray and how to obtained?? Homework Statement that's all for the questions. How do i calculate speed of o-ray and e-ray (for example, e-ray and o-ray of calcite) thank you Homework Equations none The Attempt at a Solution surfing web and reading book
10. What is resistance of a DC circuit has resistor n capacitor connect parallel

thanx a lot, that quite a lot info for me
11. What is resistance of a DC circuit has resistor n capacitor connect parallel

what about time constant T = RC, will it be zero also?
12. What is resistance of a DC circuit has resistor n capacitor connect parallel

does that mean the current won't go through capcitor branch? and that means if i want to find resistance of the circuit, it's simply R?(nothin to do with C) and wat about time constant? T = RC? will it be the same like when capacitor n resistor connect series?
13. What is resistance of a DC circuit has resistor n capacitor connect parallel

Homework Statement the title says everything, any formula that to find resistance in a DC circuit of one resistor and one capacitor connect parallel, as well as the current through each of R and C (the known values are R C and V) Homework Equations seem to me i = (V/R)e^ (-e/RC), but...
14. Pros help me with physics hw

the attachment is pending, so no one could open it (i just realized), so i am go ahead host it on imageshack and post the link here, hope everyone would help me http://img519.imageshack.us/my.php?image=85119635si7.jpg
15. Pros help me with physics hw

Homework Statement hello everybody, i had hw prob due tommorrow, but i couldn't solve, the attached file is the image of the problem (it absolutely has no virus). all known values are labeled in the picture (V, R (same for all), C1 and C2). The questions are: find curren I, and time...