# Search:

Type: Posts; User: mammothrob

Page 1 of 4 1

1. ## Thread: Bayes and total probability (Haemophilia)

by mammothrob
Replies
0
Views
988

### Bayes and total probability (Haemophilia)

Haemophilia is a sex-linked genetic disease that results in the inability of blood to clot. (A disease is sex-linked if the disease gene is located on X-chromosome.) A woman with one copy of the gene...
2. ## Thread: Annihilarator technique for y'' + 4y' + 4y = 5xy^(-2x)

by mammothrob
Replies
1
Views
1,501

### Annihilarator technique for y'' + 4y' + 4y = 5xy^(-2x)

Im having some trouble getting the answer to this promlem...

Find the general solution to the given differetial equation. Derive your trial solution using the annihilator technique.

\[...
3. ## Thread: Diff. Equation Help: (1+y^3)y' = x^2

by mammothrob
Replies
1
Views
1,360

### Diff. Equation Help: (1+y^3)y' = x^2

Determine the region in the xy-plane for which

(1+y^3)y' = x^2

This has a unique solution.

-----------------------------------------

Not really understanding what this is asking of me?
4. ## Thread: Initial Value Prob: y' = (3x^2)/[(3y^2)-4] where y(0)=1

by mammothrob
Replies
2
Views
3,305

### haha.... its funny how easy things can end up...

haha.... its funny how easy things can end up being. thanks.
5. ## Thread: Initial Value Prob: y' = (3x^2)/[(3y^2)-4] where y(0)=1

by mammothrob
Replies
2
Views
3,305

### Initial Value Prob: y' = (3x^2)/[(3y^2)-4] where y(0)=1

Im having a little issue figuring out this intial value problem.

Solve the Initial Value Problem
y' = (3x^2)/[(3y^2)-4] where y(0)=1

Looks like I can solve it as a seperable DE.

dy/dx...
6. ## Thread: Eigen question

by mammothrob
Replies
5
Views
2,284

### does the real spectral theorem have anything to...

does the real spectral theorem have anything to do with this?
7. ## Thread: Eigen question

by mammothrob
Replies
5
Views
2,284

### Eigen question

For which real numbers c and d does the matrix have real eigenvalues and three orthogonal eignvectors?

120
2dc
053

I have some thoughts on this but have not gotten too far.

The matrix in...
8. ## Thread: What is your math orinentated career / hobby?

by mammothrob
Replies
27
Views
12,996

### I avoided math through highschool and held off...

I avoided math through highschool and held off from taking it as long as I could, until I had to start the calculus series for a computer sci major. After Second semester calculus I change my major...
9. ## Thread: Linear maping

by mammothrob
Replies
7
Views
2,618

### yesss... I see it now. I was missing the...

yesss...

I see it now. I was missing the concept between standard and non-standard bases. Much appreciated.
10. ## Thread: Linear maping

by mammothrob
Replies
7
Views
2,618

### The matrix A is the matrix relative to B and B'....

The matrix A is the matrix relative to B and B'.

I mean if you Multiply A with coordinate matrix relaitve to B you get a coordinate matrix relative to B'
11. ## Thread: Linear maping

by mammothrob
Replies
7
Views
2,618

### T:R2 -----> R3 \begin{array}{l} T(x,y) = (x...

T:R2 -----> R3

\begin{array}{l}
T(x,y) = (x + y,x,y) \\
B = \{ (1, - 1),(0,1)\} \\
B&#39; = \{ (1,1,0),(0,1,1)(1,0,1)\} \\
\end{array}

The matrix for T relative to B and B' is
12. ## Thread: Linear maping

by mammothrob
Replies
7
Views
2,618

### Linear maping

T: P3 ----> P4

\begin{array}{l}
T(ax^3 + bx^2 + cx + d) = (3x + 2)(ax^3 + bx^2 + cx + d) \\
B = \{ x^3 ,x^2 ,x,1\} \\
B&#39; = \{ x^4 ,x^3 ,x^2 ,x,1\} \\
\end{array}

Find the...
13. ## Thread: Proof: Orthagonal Comp.

by mammothrob
Replies
1
Views
1,412

### Proof: Orthagonal Comp.

Prove that the orthogonal complement of a subspace of (Rn) is itself a subspace of (Rn)

-----------------------------------------------------

Let V be the orthogonal complement of S, S a...
14. ## Thread: vector triple product proof

by mammothrob
Replies
4
Views
5,032

### I think I missed something before... they book...

I think I missed something before... they book probably is refering to 3 space. I was just asumming for some reason that the vector triple product was used for vectors larger than ordered triplets. ...
15. ## Thread: vector triple product proof

by mammothrob
Replies
4
Views
5,032

### thats how I did it... for u v w being ordered...

thats how I did it... for u v w being ordered triplets. (R3)

But does that truely prove that it works for (Rn)?

Or do i need to do it somehow like this...

u = (u1, u2, u3, ... un) ...
16. ## Thread: vector triple product proof

by mammothrob
Replies
4
Views
5,032

### vector triple product proof

Im trying to prove this identity.

Let u v and w be vectors in (Rn) and <u,u> denote the dot product.

u x ( v x w ) = <u,w> v - <u,v> w

Here are my ideas on this.

I tried using the...
17. ## Thread: Let A, B be n-by-n matrices, w/ AB singular. Prove that....

by mammothrob
Replies
1
Views
2,886

### Let A, B be n-by-n matrices, w/ AB singular. Prove that....

Im stuck on this proof.

Let A and B be nxn matricies such that AB is singular. Prove that either A or B is singular.

Sooooo, here we go.

Let M = AB where is M is the given singular matrix....
18. ## Thread: LU Factorization

by mammothrob
Replies
2
Views
1,090

### LU Factorization

Im doing a LU factorization on Matrix A

A = \left[ {\begin{array}
1 & 1 & 1 \\
1 & 2 & 2 \\
1 & 2 & 3 \\
\end{array}} \right]

I reduced it to an upper triangular matricie
19. ## Thread: Matrix Inverse/Identity Proof

by mammothrob
Replies
1
Views
1,235

### Matrix Inverse/Identity Proof

This proof is looking kinda weird to me. Does this look correct?

Let (A) be a nonsingular invertable matrice.
(I) is the identity matrix

If A(A)=A, the prove that A=I

\begin{array}{l}
20. ## Thread: 4x5 Matrice Solution

by mammothrob
Replies
4
Views
3,977

### so I have my solution equations, which represent...

so I have my solution equations, which represent an infinite amount of solutions.

x + z + 3w = -1
y - 2z = 5

so to write my answer in a parametric form would this be correct?

Let z and y...
21. ## Thread: [SPLIT, MOVED] matrices and elem. ops: rows or columns?

by mammothrob
Replies
1
Views
673

### [SPLIT, MOVED] matrices and elem. ops: rows or columns?

When you do elementry row operations, do you see the matrix in columns or in rows?

I have been seeing this in rows so far, trying to get a leading one at the begining and then trying to get...
22. ## Thread: 4x5 Matrice Solution

by mammothrob
Replies
4
Views
3,977

### 4x5 Matrice Solution

soooo... I have these four equations and need to solve for four unknowns.

So I built a 4x5 matrix for it. Im useing (r1234) to denote the rows and bold font to seperate decemal numbers where they...
23. ## Thread: Fundamental Theorem Line Integrals

by mammothrob
Replies
2
Views
910

### Thanks... I have my calc III final tomorrow and...

Thanks... I have my calc III final tomorrow and that was an example on our review handout. It was freaking me out a little.
...............Back to studying.................
24. ## Thread: Exponent Problems

by mammothrob
Replies
4
Views
1,527

### well this is whats going on if I interpreted your...

well this is whats going on if I interpreted your problem right

\frac{{2^{ - 3} + 4^{ - 1} }}
{{2^{ - 3} }} = \frac{{\frac{1}
{{2^3 }} + \frac{1}
{{4^1 }}}}
{{\frac{1}
{{2^3 }}}}
25. ## Thread: Exponent Problems

by mammothrob
Replies
4
Views
1,527

### 27^{2/3} = \sqrt[3]{{27^2 }} when you have...

27^{2/3} = \sqrt[3]{{27^2 }}

when you have a constant or vaiable raised to a fration like above the denominator of the fraction becomes the index and the numerator hangs on to the constant or...
Results 1 to 25 of 99
Page 1 of 4 1