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Lv 1240 points

Physicist in Training

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I am an undergraduate student in physics. I am here to ask questions that I do not know the answers to, and I am also here to answer questions that I know the answers to. I am using this site as a way to keep me refreshed on what I have learned as well as to learn. If I have answered your question and it is incorrect please notify me so that I may review my answer.

  • How do I solve this problem linear algebra, eigenvalues, eigenvectors, and orthogonal projections?

    I am part way done with this problem.... I don't know how to solve part e or part f. Any help or clues would be greatly appreciated. I have been trying to figure this out for a couple days now.

    W={<x,y,z>, x+y+z=0} is a plane and T is the orthogonal projection on it.

    a) Find the basis of {v1, v2} for this subspace.

    I found the basis of W to be v1=<-1,1,0> and v2=<-1,0,1>

    b) These basis vectors are basis vectors for what eigenvalue?

    I found the eigenvalue to be zero after multiplying W with v1 and v2.

    c) Show that n=<1,1,1> is orthogonal to {v1 ,v2}

    I just took the dot product of n*v1 and n*v2 and both were zero

    d) Show that n is orthogonal to all of W

    My reasoning is that n is orthogonal to all of W because W is a linear combination of {v1 ,v2}

    e) n is an eigenvector for T for what eigenvalue

    ??????

    f) Using matrix with eigenvectors and one for eigenvalues, find the standard matrix of T.

    ??????

    2 AnswersMathematics1 decade ago
  • How do I solve this problem in linear algebra (eigenvectors, and eigenvalues)?

    I am part way done with this problem.... I don't know how to solve part e or part f.

    W={<x,y,z>, x+y+z=0} is a plane and T is the orthogonal projection on it.

    a) Find the basis of {v1, v2} for this subspace.

    I found the basis of W to be v1=<-1,1,0> and v2=<-1,0,1>

    b) These basis vectors are basis vectors for what eigenvalue?

    I found the eigenvalue to be zero after multiplying W with v1 and v2.

    c) Show that n=<1,1,1> is orthogonal to {v1 ,v2}

    I just took the dot product of n*v1 and n*v2 and both were zero

    d) Show that n is orthogonal to all of W

    My reasoning is that n is orthogonal to all of W because W is a linear combination of {v1 ,v2}

    e) n is an eigenvector for T for what eigenvalue

    ??????

    f) Using matrix with eigenvectors and one for eigenvalues, find the standard matrix of T.

    ??????

    3 AnswersMathematics1 decade ago
  • Did I solve this system of differential equations right?

    The problem is...

    Initially, there are 60 squirrels and 60 raccoons in an ecosystem. r(t) = raccoon population in t years, s(t)= squirrel population in t years.

    r'(t) = 5/2r(t)-s(t) and s'(t)= -1/4r(t) +5/2s(t)

    solve for s(t) and r(t)

    ************************************

    My answer....

    r(t)= 90e^(2t) - 30e^(3t)

    s(t)= 45e^(2t) +15e^(3t)

    Now obviously if t=0 then they both equal 60 so it looks right, but I would like some confirmation.

    1 AnswerMathematics1 decade ago
  • How do I solve this population problem involving linear algebra and differential equations?

    The problem is...

    Initially, there are 60 squirrels and raccoons in an ecosystem.

    r(t)= raccoon population in t years

    s(t)= squirrel population in t years

    r'(t)= 5/2r(t) - s(t)

    s'(t)= -1/4r(t) +5/2s(t)

    solve for s(t) and r(t)...

    I am completely lost. I have looked in many books and I can hardly find any information on this topic.

    2 AnswersMathematics1 decade ago
  • Will you please help me with this algebra/physics problem?

    So I am reading my textbook and I come to the problem...

    (x-L)/(x)=1/2

    the answer is

    x = 2L

    I do not see how they came to that answer. Can you please explain it to me?

    5 AnswersMathematics1 decade ago
  • My power steering broke at the mechanics shop. Do I have to pay for repairs?

    Like I asked. I went to the garage to give my mechanic the clip for the wipers when he said, "they just pulled the truck out and the power steering line blew." Do I have to pay for this repair?

    6 AnswersMaintenance & Repairs1 decade ago
  • How do I find a German pen pal?

    Hello,

    I am taking German this semester and I will be taking it next semester also. I would like to find a German pen pal so I can increase my understanding of the german language and not forget what I have learned. I have found websites that can connect people, but they look sketchy at best. Does anyone know any good websites to find a German pen pal?

    Thanks.

    3 AnswersLanguages1 decade ago
  • Java and using the German language.?

    I am trying to write a computerized test so I can study for my German class, but I don't know how to import the German language or use umlauts or other special characters. I googled this several different ways but I just don't know where to go for this info.

    2 AnswersProgramming & Design1 decade ago
  • What is the most amount of felony charges that a person has been convicted of?

    I was looking up offenders in an Ohio offender database and found that a guy that was charged with 151 felonies (most come from robberies).

    Is there anyone that has had more?

    2 AnswersLaw Enforcement & Police1 decade ago
  • Where does the Gallup poll get most of its revenue?

    I tried to google this and find the answer, but I cannot. My guess is that it comes from subscriptions to their service from media sources such as Fox News, CNN, MSNBC, etc.... Then I am sure that some of the revenue comes from advertisements on their site. However, I am not sure if politicians spend money on the polls eventhough I am sure that they are quite interested in the results.

    1 AnswerOther - Politics & Government1 decade ago
  • How do I start this... Calculus 1 Maximum Volume.?

    I am not on here so people can do my homework so, I would appreciate if you didn't give me a full answer. I am stuck on the following problem and I do not know where to begin or what to do.

    A cylinder is inscribed in a right circular cone of height 5 and radius (at the base) equal to 6. What are the dimensions of such a cylinder which has maximum volume?

    1 AnswerMathematics1 decade ago
  • Finding critical points in Calculus 1?

    2 asks for the critical points of

    f(z)=(1+4z)2(4−z2)4

    I came up with the derivative as being....

    f'(x)=2(1+4z)(4)(4-z^2)^4 + (1+4z)^2*4(4-z^2)^3(-2z)

    I then factored out (1+4z)(4-z^2)^3

    I solved for these and got (-1/4) & (+/- 2)

    After that I had gotten

    (32-8z^2)+(8z+32z)

    factored out the eight and then used the quadriatic formula to obtain..... (-1) and (4)

    so that leaves me with the following answers which I believe are right, but they may not be.

    2,-2,-(1/4),4,-1,0

    1 AnswerMathematics1 decade ago
  • Can you please check my derivative.?

    The equation is

    f(z) = (1+4z)^2 (4-z^2)^4

    I have without simplifying at all......

    f'(z) = 2(1+4z)(4)(4-z^2)^4 + (1+4z)^2*4(4-z^2)^3(-2z)

    The chain rule has been driving me mad and I just want to make sure I have this correct before I continue with the algebra.

    1 AnswerMathematics1 decade ago
  • Help w/ derivatives....Am I even doing this right?

    The question is the to differentiate with respect to y (or find y').

    The question...

    sin(6x+y^6) = 3y-x^5

    My answer.... (I am sure that it is wrong)

    dy/dx = (3-5x^4)/((6+6y^5)cos(6x+y^6))

    1 AnswerMathematics1 decade ago
  • Can someone help me find this derivative?

    ln(19x^4)-8y^5=x^4e^y

    So far I have

    (1/19x^4)-(40y^4)*(dy/dx)= ?

    I am stumped as to what to do with the x^4e^y

    5 AnswersMathematics1 decade ago