# Search results for query: *

1. ### Can someone please delete my account?

Cristo, thanks, but please don't jump to conculsions and accuse me of something I have not done. I HAVE NOT CHEATED IN ANY WAY AND DID NOT INTEND TO USE THIS FORUM FOR THAT. If you look at my previous posts you would realize that! I have only ever asked for help with questions that I have...
2. ### Can someone please delete my account?

Not getting in trouble from my uni tutor for asking for help with assignment questions...
3. ### Can someone please delete my account?

Well it is ridiculous that you force people to still hold an account on here. What a friendly place! Is it just so you can get member numbers? Anyway, Cristo, thanks for pointing that out to me have a nice day :)
4. ### Can someone please delete my account?

But it is my account... I opened it, I should be allowed to close it... Any other forum would respect the wishes of its user in a matter such as this, and what I am asking does not impede the forum at all... If for some reason you can't find anyway to delete it, I would rather not be banned...
5. ### Can someone please delete my account?

I would like to close my account on here, can someone please advise me how to do so. Thanks
6. ### Determining the static and kinetic coefficients on an incline of wood on wood

Homework Statement This was a lab task in which we are asked: Determine the static and dynamic coefficients of friction for a block of wood of mass 82.2grams on a plank of wood. PART A: To determine the static coefficient we found the angle at which point the block just started to...
7. ### Entropy Change of an expanding gas

Yep I figured out the right anwer which is 14.9 I don't know what I meant with that massive negative figure! Thanks for you help anyway.
8. ### Entropy Change of an expanding gas

Two moles of an ideal gas undergo a reversible isothermal expansion from 1.97×10−2 m^3 to 4.82×10−2 m^3 at a temperature of 20.0 C. What is the change in entropy of the gas? WORKING: Using \DeltaS = nRIn(V2/V1) = 2(8.31*ln(4.82*10^-2/1.97*10^-2) ANS = -138.20 J/K Is this...
9. ### Finding polar form of 1/Z

I understand that that is how the question is written and the sign indicates the point position in the plane. Sorry I worded the question wrong. Basically, z = \sqrt{}3 + i Polar form of this is: 2( cis \pi/6 ) then working out 1/z the answer is 1/2 (cis -\pi/6) I do not know why...
10. ### Finding polar form of 1/Z

Hi There. I was given this question and the answer: Find the polar forms of 1/z where z = \sqrt{}3 + i and 1/z where z = 4\sqrt{}3 -4i Answers respectively are: 1/2 cis(-\pi/6) 1/8 cis(\pi/6) Can someone please explain to me why it is that the sign of the argument...
11. ### Polar form of complex numbers

Thanks so much for that :)
12. ### Polar form of complex numbers

Hi There, Can someone please tell me where I can find a table/ data that converts radians to surds. I don't know what to call it but, for instance to tan^-1(-1) = -Pi/4 and, cos(-pi/6) = root3/2 ? Thank you :)
13. ### Expressing complex numbers in cartesian form

4 Questions: (1 + i) / (1 - i) Ans: i (2 + 3i) / (5 - 6i) Ans: (-8+27i)/61 1/i - (3i)/(1-i) Ans: (3-5i)/2 i^123 - 4i^9 - 4^i Ans: -9i Could someone please explain the method (detailed) as to how these answers were obatined? I understand other questions in the same...
14. ### Finding inverse of a matrix and solving given equations.

Its so hard to put all these number and boxes back into simple ax = b and again rearrange. Thanks cristo for your help!
15. ### Finding inverse of a matrix and solving given equations.

So how would I know that I have to multiply the left by the inverse of A to find the answer? Is there some basic principle or law that I am unaware of?
16. ### Matrix Help: Solving for X

Cristo if you have a chance could you please look at the other post i made tonight as no one has replied yet and I am more concerned about not understanding that one... Sorry to be a pain and I understand if you can't be bothered! ciao
17. ### Matrix Help: Solving for X

Hahahaha derr... So sorry yes I just realized the answer is really REALLY simple I was forgetting to multiply the whole RHS not just DC^-1 by a denominator of 1/A. Thank you muchly for your help though :)
18. ### Matrix Help: Solving for X

well I don't understand how they have attached an extra A^-1 to the B for the final part of the solution. Why wouldn't it just remain as -B?
19. ### Matrix Help: Solving for X

[SOLVED] Matirx help please Hey, I have a quiz tomorrow and I was hoping someone could explain how this answer was formed from a question on the practice quiz. Suppose A, B, C, D are square matrices of the same size and that A and C are invertible. Given that AX + B = DC^-1 ( Sorry it's...
20. ### Finding inverse of a matrix and solving given equations.

[SOLVED] Finding inverse of a matrix and solving given equations. Hi, I have a quiz tomorrow and I am looking at the sample quiz right now but I don't understand how the answers work! Here is the question: Find the inverse of the matrix A= -1 3 3 -2 1 2 0 1 1 Hence...
21. ### Theta_max = 53.8° Acceleration of Hoop on Inclined Ramp

A circular hoop of mass m, radius r, and infinitesimal thickness rolls without slipping down a ramp inclined at an angle theta with the horizontal. View Figure PART A. What is the acceleration of the center of the hoop? Express the acceleration in terms of physical constants and all...