Recent content by toofle

Binomial[5 + 14 - 1 , 5-1]^2 = 9363600 ?

I don't get it. (5+1-1 nCr 5) = 1, I assume that's not how you mean? But I don't get what you mean since (I assume) all cans must always be distributed.

so (5+14-1 nCr 5)^2?

If I first hand out two of each kind to everyone then I have 2*14 left. Then I can distribute the rest like this: 5^14 * 5^14 = 5^28 = approx 3.73*10^19 Correct?

I thought that at first but then I wasn't sure if how I distributed them mattered or not. But the rest still seems very complicated. I could give the first student 28 cans and the rest 0 then 14 of one, 13 of the other or 13 of one and 14 of the other and one of the others get one and the...

Homework Statement In how many ways can 24 cans of Fanta and 24 cans of Cola be distributed among five thirsty students so that each student may (a) at least two cans of each variety? (2p) (b) at least two cans of a variety, at least three cans of the other variety? (3p)Homework Equations The...

actually you are right. I forgot to step with 2 in my TI82 as well. Thanksm but I get it now.

I meant sum from 2 to 32 with step=2, ie 2,4,6,8,...,32. for got to write that but the answer was calculated that way. ofc, (16 nCr 1) * (16 nCr 1). then the same for 2,3,4 etc. I get it.

Homework Statement The screwengineer Pelle has a box with 16 black screws and 16 white screws. a. In how many ways can he pick an even(at least 2) amount of screws from the box? b. Pelle randomly chooses one of the alternatives in (a), what's the chance that gets as many white as black...

Homework Statement Solve the difference equation Homework Equations y[n+2]-3y[n+1]+2y[n]==4n*2^n, n>=0 y0=0,y1=1 The Attempt at a Solution 1. Homogenous solution: Characteristic equation => r^2-3r+2==0 <=> r1=1,r2=2 => yhn = C1*1^n+C2*2^n 2. Particular solution: ypn = ? I...

Homework Statement Find the transfer function and the impulse response for the system: y'(t) + y(t) = x(t) x = {1 if 0<=t<1,0 1<=t} Homework Equations d/dt y(t) ~ sY(s) -y(0) The Attempt at a Solution I transform into the laplace-domain: sY(s) - y(0) + Y(s) = X(s)...

Why is the function decreasing the fastest in the direction of the negative of the gradient? Just because it increases the fastest in the direction of the positive of the gradient why does this have to mean it has to decrease the fstest in the negative of the gradient? If you stand facing a...

Homework Statement Solve the first order difference equation. Homework Equations x[n] - x[n-1] = n(n+1)/2 x[1] = 1 The Attempt at a Solution Homogenous solution: Characteristic equation: r - 1 = 0 <=> r = 1 => yhn = C * 1^n = C Particular solution: ypn = ? I'm supposed to...

Homework Statement Studying for an exam, this is a question from an earlier exam: Calculate: sum k from 1 to infinity, 1/k^2 I have from previous question: f(t)=pi+sum n from 1 to infinity: 2*(-1)^n/n*sin(nt) f(t)=pi-t, -pi<=t<pi So i need to rearrange this to calc the sum...

A graph can be represented by an adjacency matrix but how is that a real mathematical matrix and not just a table? A matrix is part of an equation system Ax=B but what is x and B in this case if A is the adjacency matrix? For example Google does PageRank with Eigenvalues but what would...