Recent content by freshlikeuhh

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    Graduate Unclear About Proof: Confused by Bounded Above Sets and Functions

    http://i.imgur.com/uhqc5.jpg I am trying to make sense of this proof in my textbook and find myself confused by a few things. I will try to present my question in the order that they come to me as I read the passage: 0) When defining the set A, "f is bounded above on [a,x]", x serves as a...
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    Undergrad Tips For Algebraic Manipulation

    I have a really bad math background, so sometimes I struggle with or am just a little slow with some algebraic things, while I can handle more abstract stuff fairly well. Lately I've been running into certain types of problems in my algebra class which are proving to be time-consuming for me...
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    Undergrad How Do These Linear Algebra Concepts Align with Definitions and Vector Spaces?

    Thank you very much for the reply. It has certainly cleared things up for me. Oops. Seems like I got it backwards. But polynomials can be thought of as functions; so for a polynomial of finite dimension, does it make sense to think of it as a list of functions?
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    Undergrad How Do These Linear Algebra Concepts Align with Definitions and Vector Spaces?

    I am studying for an upcoming exam and am, to this end, re-reading my textbook at a slow rate to identify anything I'm not completely certain about. Linear algebra is very cumulative and proofs require a good understanding of all definitions. So I will post some questions (for which I seek...
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    Prove Continuity of f at a w/ f(x+y)=f(x)+f(y)

    Well, I understand how the property f(x+y)=f(x)+f(y) is used to demonstrate f(0)=0 and obviously it is employed to expand f(a+h)=f(a)+f(h). I understand that this step is supposed to demonstrate the continuity of all a, but then why is h->0, and how exactly is continuity of a demonstrated if a...
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    Prove Continuity of f at a w/ f(x+y)=f(x)+f(y)

    Homework Statement Suppose that f satisfies f(x+y) = f(x) + f(y), and that f is continuous at 0. Prove that f is continuous at a for all a. Homework Equations f(x+y) = f(x) + f(y) Limit Definition Continuity: f is continuous at a if the limit as x approaches a is the value of the...
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    Undergrad What is the Limit Definition for Proving a Function Approaches 0?

    Hi. I'm a first-year calculus student and I'm fairly behind with my work. The transition is tough and when i read my textbook, I don't fully absorb everything. I thought I would post an example problem whose solution I do not follow completely, since it is fairly important in the scope of...
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    What is a Basis for a Polynomial Subspace with Specific Roots?

    Ohh. I think I follow; by plugging in for a, the elements we obtained form a basis? That is, in each case of {(x2-x), (x3-x), (x4-x)}, 0 and 1 are roots: e.g., x2-x = x(x-1).
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    What is a Basis for a Polynomial Subspace with Specific Roots?

    Thanks for the quick reply, btw. I think I catch your meaning. That means the coefficients must sum to 0, for every element in the subspace(?). Given your helpful reply, I don't feel inclined anymore to fix x(x-1) as an element. That is, the fact that 0 is a root follows from there being...
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    What is a Basis for a Polynomial Subspace with Specific Roots?

    Homework Statement Let P_4(\mathbb{R}) be the vector space of real polynomials of degree less than or equal to 4. Show that {{f \in P_4(\mathbb{R}):f(0)=f(1)=0}} defines a subspace of V, and find a basis for this subspace. The Attempt at a Solution Since P_4(\mathbb{R}) is...
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    Graduate Linear Independence: Polynomial Example

    Ah, that makes it all clear now. Thanks!
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    Graduate Linear Independence: Polynomial Example

    Hello everyone. I was going through my Linear Algebra Done Right textbook that threw me off. I hope this forum is appropriate for my inquiry; while there is no problem I'm trying to solve here, I don't know whether just asking for clarification would belong to the homework forum instead. If...