# Search results

1. ### Double integral and reversing order

Thanks for the hint!
2. ### Double integral and reversing order

Homework Statement http://img10.imageshack.us/img10/3390/55486934.jpg [Broken] Homework Equations This is what I was thinking: tan−1(∏x)−tan−1(x)=∫^{g(x)}_{f(x)}h(y)dy The Attempt at a Solution I don't really understand how to do this question
3. ### Matrix transformation

Homework Statement just wondering, what exactly is T2(v)=0? is it T(T(v))=0 or T(v)*T(v)=0?? Homework Equations The Attempt at a Solution
4. ### Find a basis of U, the subspace of P3

Yes. But the question in my assignment is Find a basis of U, the subspace of P3 d) U = {p(x) in P3 | p(7) = 0, p(5) = 0,p(3) = 0,p(1) = 0} and I wrote no basis
5. ### Conditional Probability: probability of having a girl.

1/2 it doesn't matter
6. ### Find a basis of U, the subspace of P3

does that mean the basis exist {1,x,x2,x3}?
7. ### Find a basis of U, the subspace of P3

can i write does not exist? thanks!
8. ### Quick ! T(A) = Tr(A)

Quick plz! T(A) = Tr(A) Homework Statement Let T : M22 define as T(A) = Tr(A). Show that T is a linear transformation and find the dimension of ker T. Homework Equations The Attempt at a Solution what is Tr(A)? is it trace(A), or rT(A) , r is a real number?
9. ### Find a basis of U, the subspace of P3

so the basis would be {(x - 7)(x - 5)x,(x - 7)(x - 5)}? dim=2 plz answer this one U = {p(x) in P3 | p(7) = 0, p(5) = 0,p(3) = 0,p(1) = 0} does p(x) exist? it has 4 degree(x - 7)(x - 5)(x - 3)(x - 1), but P3 is a set of third degree, so it does not exist is that right?
10. ### Find a basis of U, the subspace of P3

Homework Statement Find a basis of U, the subspace of P3 U = {p(x) in P3 | p(7) = 0, p(5) = 0} Homework Equations The Attempt at a Solution ax3+bx2+cx+d p(7)=343a+49b+7c+d=0 p(5)=125a+25b+5c+d=0 d=-343a-49b-7c d=-125a-25b-5c ax3+bx2+cx+{(d+d)/2} -->{(d+d)/2}=2d/2=d...
11. ### Quick diagonalize matrix (row reduce)

And using this calculator http://wims.unice.fr/wims/en_tool~linear~matrix.html I found that Value Multiplicity Vector 6 1 (0,1,1) 3 2 (1,0,1), (0,1,-1/2) (1,0,1) and (0,1,1) is right, but (0,1,-1/2) is different to the website , which is (1/2,1,0) I m confused..
12. ### Quick diagonalize matrix (row reduce)

oh i I figure it out... I was just asking Do I get the same eigenvector (which is 0,1,1) if I transform -3,0,0 0,1,-1 0,0,0 to rref In reduced row-echelon form (RREF), the matrix above is 1 0 0 0 1 -1 0 0 0 The only thing that changed is row 1. You'll get exactly the same...
13. ### Quick diagonalize matrix (row reduce)

quick plz..diagonalize matrix (row reduce) Homework Statement http://www.math4all.in/public_html/linear%20algebra/chapter10.1.html 10.1.5 Examples: (ii) this part: ----------------------------------------------------------------------------------------- are both eigenvector for the...
14. ### Quick questionmatrix (similar~)

Homework Statement just wondering if A is similar to the reduced(or non-reduced) row echelon form of A Homework Equations The Attempt at a Solution
15. ### Quick Find a Basis

Homework Statement http://en.wikibooks.org/wiki/Linear_Algebra/Vector_Spaces_and_Linear_Systems/Solutions Problem 14 Can answer be (3,1,2)T (2,0,2)T? also, can I reduce the matrix without transpose? thanks Homework Equations The Attempt at a Solution
16. ### Subspace question

I got it, thanks!
17. ### Subspace question

is there another way to prove it? like using x1 or y2
18. ### Subspace question

not in the set, but why is x^2+y^2 equal to one?

yes, (2,0)
20. ### Subspace question

oh , (1+1, 1-1) (2,0) not in (x,y) am i correct? or can you explain to me in word?
21. ### Subspace question

Homework Statement [PLAIN]http://img683.imageshack.us/img683/4530/unledkw.jpg [Broken] can someone please explain why it is not closed under addition??? My textbook did not explain very well, but I understand this can be zero vector and it is closed under scalar multiplication. thanks...
22. ### L'Hopital's Rule

I differentiated like 5 times, I still got 0.. I notice that there is always a x*cos(9x) in the nominator...which make whole thing equal to 0..
23. ### L'Hopital's Rule

ok ty, I will do it later, I have class now
24. ### L'Hopital's Rule

\lim_{x \to 0} \frac{5x(\cos(9x) - 1)}{\sin(5x) - 5x} I tried After the second derivative, the denominator is still zero... -25sin(5x)
25. ### L'Hopital's Rule

I'm not sure, it's an assignment from the internet, it should be sin(5x-5x) , cause it ask you to use L'Hopital's Rule sin(0)=0
26. ### L'Hopital's Rule

Homework Statement lim x->0 5x(cos 9x-1)/sin 5x-5x Homework Equations The Attempt at a Solution answer is 243/25 The derivative of sin 5x-5x is always 0, dunno know how to do it...
27. ### Differentiating (2x - 10 + e)^(y + 8à = e^(x - 6)

ok , i see it now, e is a constant, that's why.. ty
28. ### Newton cooling law

Homework Statement An object of temperature 60oF is placed in a medium maintained at a constant temperature moF. At the end of 5 mins thetemperature of the object is 45 oF and after another 5 mins its temperature is 36 oF. Find m Homework Equations y=cekt+m The Attempt at a...
29. ### Differentiating (2x - 10 + e)^(y + 8à = e^(x - 6)

Homework Statement (2x-10+e)^(y+8)=e^(x-6) value of dy/dx at the point, (5,-9) Homework Equations The Attempt at a Solution (y+8)ln(2x-10+e)=x-6 y' ln(2x-10+e)+(y+8)(2+e)/(2x-10+e)=1 ln(2*5-10+e)=1 y'+(-9+8)(2+e)/e=1 y'-(2+e)/e=1 y'=1+(2+e)/e but the answer is (2+e)/e, I don't know...
30. ### Quick matrix question

Nevermind, I just figure it out... sorry, i was just confused on something