Recent content by DMOC

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    Advice: TA for Multivariable or Linear

    Hi everyone, I am interested in applying to be a teaching assistant in my university's multivariable calculus class or linear algebra class. I took both of these courses already and seem to like them equally well. I will have solid recommendations and grades. Any recommendations on which...
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    What is the Induction Process for Finding det(alpha*A)?

    Old topic: https://www.physicsforums.com/showthread.php?t=194725 I have a question that's the same as the one in the old topic/thread I linked to above. At the last post, I am trying to figure out how to carry out the induction process. \sum_{j=1}^n (-1)^{i+j} a_{ij} det(\alpha A_{ij})...
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    Proving Vector Space Properties for a Set of Scalar Multiples of [1,3,2] in R3

    For closure under addition, I would suggest ------------------------- Let a<1,3,2>, b<1,3,2> \in R3, a<1,3,2> + b<1,3,2> = <a1+b1, a3+b3, a2+b2> <a1+b1, a3+b3, a2+b2> \in R3 Closure under addition holds. --------------------------- I don't know how strict your...
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    Proving Vector Space Properties for a Set of Scalar Multiples of [1,3,2] in R3

    You'll probably catch this, but the c + 3 should really be a c + 2. A better way to write closure under addition would be the way Mark44 wrote it. Also, I recommend adding a confirmation statement such as "Closure under addition holds!" at the end of every specific property proof.
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    Are x1, x2, and x3 linearly dependent in R^n?

    Yes, that should be correct ... my bad. But would the longer method be valid? i.e. mathematically legal?
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    Are x1, x2, and x3 linearly dependent in R^n?

    y1 = x2 - x1 y2 = x3 - x2 y3 = x3 - x1 x1, x2, x3 are linearly independent in R^n Is that true for y1 y2 and y3? --- Well, normally with linear indepence problems, I can set up a matrix and check to see if the row echelon form has free variables or not, or I can calculate the...
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    Exploring REU Opportunities: Join the Discussion

    Hey guys, I'm just curious about these REUs because I may be applying to possibly 10 or so next summer (when I'll be a rising junior, so it isn't the end of the world if I get rejected from all). Are these REU's generally one of the best ways to get a research paper or project done? As compared...
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    Solve Soft Drink Equation Homework Statement

    Okay guys apparently this problem has additional steps. I know this equation is right, but now I'm asked "If the advertising budget only allows $100 per day, what price should I charge (per bottle) to start having a profit in two days? So does this mean that I have to plug in 2 for t in...
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    Solve Soft Drink Equation Homework Statement

    The words "sep. of variables" doesn't ring a bell but the method does. I was eventually able to solve the full problem, ending up with: B(t) = \frac{Me^{\frac{-40t}{M}} - M}{-0.08} Thanks everyone. :)
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    Solve Soft Drink Equation Homework Statement

    When you refer to DE, you're talking about the first equation I have, right? I copied that one straight off of my notes. :) So for my solution, I have to take this D.E. I have and solve for B. Does that mean I have to do stuff like take the integrand of both sides? (so that dB/dt becomes B(t)? ).
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    Solve Soft Drink Equation Homework Statement

    Homework Statement A soft-drink manufacturing company introduces a new product. The company's salespeople want to predict the number of bottles per day they will sell as a function of the number of days since the product was introduced. One of the parameters will be the amount per day spent...
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    Convergence of a Series with Alternating Terms: Finding Values of X

    Wait so I can't use the alternating series test with a non alternating series ... wow I'm going to kick myself in the @%$@# for overlooking this. So I assume I just use like a comparison test for 1/ln(k+2) with 1/k (diverges) since ln makes values of k smaller so the frac. gets bigger.
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    Convergence of a Series with Alternating Terms: Finding Values of X

    Homework Statement Determine values for x where \sum \frac{(2^k)(x^k)}{ln(k + 2)} converges if k goes from 0 to infinity. Homework Equations Limit test and alternating series test. The Attempt at a Solution I used the limit comparison test to test out ak+1 and an and I ended up...
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    What is the method for finding inflection points for a given function?

    Anyone have their opinions on what I should add to the answer?
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