Recent content by Bob Ho

Homework Statement A solid is definited by the inequalities 0\leqx\leq1, 0\leqy\leq1, and 0\leqz\leqx2+y2. The temperature of the solid is given by the function T=25-3z. Find the average temperature of the solid. The Attempt at a Solution I solved the integral, however I could not...

Hi, just wanted to quickly find out what you would class soil which has water content which is lower than its liquid limit, but above its plasticity limit, thanks. Edit: I'm starting to think it just acts as a plastic hopefully that's right

Show by induction that the nth derivative f(n)(x) of; f(x)=sqrt(1-x) is f(n)(x)= -\frac{(2n)!}{4^{n}n!(2n-1)}*(1-x)(1/2)-n for n \geq 1.

Homework Statement Barium metal crystallizes in a body-centred cubic lattice. The density of the metal is 3.50gcm^-3. Calculate the radius(in pm) of a barium atom. M(Ba)=137.3g/mol , NA = 6.022x10^23/mol The Attempt at a Solution For 1 unit cell: m=2x137.3/6.022x10^23...

Hi, sorry to disturb you, But with the equation f(x)= x^2+2x/(x-2)^2 I need to find the intervals at which f(x) is concave up, and down. I found f '(x)= (2x+2)(x-2)^2 -2(x-2)(x^2+x)/((x-2)^4) From there I equated it to 0, and found the critical points to be x=2,-2/3. However, I...

Homework Statement Determine the mass of air above a certain area on a typical winter day between ground level and 470m. Homework Equations The Attempt at a Solution I found the total area which I need to find the mass of air for, which gave me 2.05x10^9m^2 I times that by the...

Just a simple flat round sieve is suitable.. I am doing manufacturing drawing, I may just do orthographical drawings for the sieve, Is that suitable do you reckon?

Hi, Id like to figure out how to draw a sieve isometrically. Just a simple mesh sieve would be fine.. No Matter which way I look at it.. I cannot seem to find a way to draw it isometrically, would anyone be able to provide me a link or a useful tip to help me draw it thanks?

From that I'm assuming the general formula I need is I-B^k=(I-B)(I+B)? I hope that's right, thanks a lot you are very helpful

I do not understand how this leads to me getting a formula for the inverse of (I-B). The only equation I can think of that relates to this is (I-B)^-1(I-B)=I... and I wouldn't have a clue how to change that if the powers of B were changing... any other ideas to get my brain into gear?

Homework Statement If B is any nilpotent matrix, prove that I-B is invertible and find a formula for (I-B)^-1 in terms of powers of B. The Attempt at a Solution If I make a matrix <<ab,cd>> then if 1/(ad-bc)\neq0 then the matrix has an inverse. Since I think all nilpotent matrices...

Thanks a lot! I figured out A^3=0 so I am assuming the nilpotent matrix is of index 3. I'm not sure how you managed to get the equation "(I-A)*(I+A+A^2)=I." I just did I=(I-A)^-1 -A - A^2. Would that also be suitable?

Homework Statement A square(nxn) matrix is called nilpotent of index k if A\neq0, A^2\neq0,...A^(k-1)\neq0, But A^k=0 for some positive integer K Verify that A={{{021,002,000}}} is nilpotent. What is its index? Show that for this matrix (I-A)-1= I + A + A^2 The Attempt at a...

Homework Statement y=a0+a1x+a2x^2+a3x^3+a4x^4+a5x^5 (a0,a1...,a5, are fixed real numbers) passes through the points (-2,21), (-1,7), (0,-10), (1,-8), (2,20), (3,9) Question: Write down a 6x6 matrix A such that; ... .a0... ...21 . . .a1... ...7 . . .a2...

Yes you are correct, For the very first question(Solving the system), I made x4=t to prove there are infinite solution. Which got me x1=t+10, x2=t+60, x3=t+60. I'm assuming that proves that the solutions are infinite? For the Final Subquestion (sorry this will be the last) Q.) To Reduce...