Recent content by RPierre

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    Diffrentiating Piecewise Function

    Homework Statement Let L\in R and define h(x) = \begin{cases} sin(1/x) & \text{ if } x \neq 0 \\ L & \text{ if } x = 0 \end{cases} Prove that h is not continuous at 0 Homework Equations My Professor gave us the hint "Prove by contradiction, taking \epsilon...
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    Finite Elements in a Set of Rational Numbers Proof

    Homework Statement This problem is insanely intuitive. Define f : (0,1) \rightarrow \Re by f(x)=\begin{cases} 1/q&\text{if } x \neq 0 \text{, is rational, and }x = p/q \text{in lowest terms}\\ 0&\text{otherwise }\end{cases} Suppose \epsilon > 0. Prove that there are at most a...
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    Proving the One Sided Limit Theorem: A Rigorous Approach

    Homework Statement Prove that the limit as x->c of f(x) = L if and only if both one sided limits also = L Homework Equations Has to be an epsilon delta proof The Attempt at a Solution Being an if and only if, I have to do two cases : If A, then B. and if NOT A, then NOT B, logically...
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    Epsilon-Delta Proof of limit approaching infinity

    **DISCLAIMER - I am super bad at LaTeX** Homework Statement Prove \lim_{x \rightarrow \infty}\frac{1}{1+x^2} = 0 Homework Equations I Think I proved it, but I feel like I'm missing something to make this a proof of ALL \epsilon>0 and not just one case. Maybe I did it right. I...
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    Prove if S is Open and Closed it must be Rn

    This is my first assignment ever with topological proofs, so bear with me. first, what is the map you defined , and why did you define it? Is that to say that any subset within S must also be open and closed? secondly, I've never encountered the idea of being "connected" before. I took the...
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    Solving the Derivative of f(a): A Frustrating Homework Problem

    I'm not familiar with LaTex and assumed he wasn't using leibniz notation by the prime notation used and the level of calculus, so I simply whipped up a solution with simple principles. I'm sure the original poster got the point as the question was able to be resolved. Thanks for pointing that...
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    Equation of Tangent Line Parallel to x+2y-6=0 for f(x)=x^2-x

    First, you must simplify your line for y = mx + b form. x + 2y - 6 = 0 -> x - 6 = -2y -> \frac{x-6}{-2} = y -> y = \frac{-1x}{2} + 3 Next, to find a line tangent to f(x), we take it's derivitive f'(x) = 2x - 1 Compare the two slopes. 2 and -1/2. These are in fact...
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    Solving the Derivative of f(a): A Frustrating Homework Problem

    I'll simplify this for you. See if you can solve the question from here: First, FOIL the numerator. Next, solve all of our components separately, so: h'(x) = \frac{d}{dx} (0.5t + 2)1/2 = \frac{1}{2}(0.5t +2)-1/2 * 0.5 <By Chain Rule> = \frac{1}{4}...
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    Prove if S is Open and Closed it must be Rn

    The main question: Let S be a subset in Rn which is both open and closed. If S is non-empty, prove that S= Rn. I am allowed to assume Rn is convex. Things I've considered and worked with: The compliment of Rn is an empty set which has no boundaries and therefore neither does Rn. Therefore...
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    Understanding the Boundary Theorem in Analysis: A Proof Guide | PhysicsForums

    Hey PhysicsForums, This is my first time here but I have seen many knowledgeable responses to tough questions and I truly am stumped. My question is as follows (This a third year Analysis course in my Mathematics undergrad degree): 1. Let A and B be Subsets of RN with Boundaries B(A) and...
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    Tricky Kinematics Problems - Desperately

    Homework Statement I am new to this board, but I am at my wits end trying to solve this problem. If anyone could provide a somewhat detailed solution i would forever be in debt, thanks! One car, located at position (-29.9 , 0 ) is traveling at 12.7 m/s ( +x) Another Car, located at...
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