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Homework Help: Find a basis and dimension of a vector space

  1. Dec 14, 2015 #1
    1. The problem statement, all variables and given/known data
    Find basis and dimension of [itex]V,W,V\cap W,V+W[/itex] where [itex]V=\{p\in\mathbb{R_4}(x):p^{'}(0) \wedge p(1)=p(0)=p(-1)\},W=\{p\in\mathbb{R_4}(x):p(1)=0\}[/itex]

    2. Relevant equations
    -Vector spaces

    3. The attempt at a solution
    Could someone give a hint how to get general representation of a vector in [itex]V[/itex] and [itex]W[/itex]?
  2. jcsd
  3. Dec 14, 2015 #2

    Simon Bridge

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    Homework Helper

    Look in your course notes when it talks about "general representation of a vector".
    You have definitions of the vector spaces - so start with what the symbols turn into in English.
  4. Dec 14, 2015 #3
    I'm not sure what the operator ^ means in the definition of ##V## so I can't help.
    For ##W##, you can notice that ##W = (X-1) \mathbb{R}_3[X] ## is isomorphic to ##\mathbb{R}_3[X]##, so what can you say about the dimension of 2 isomorphic vector spaces ? Secondly, a vector space isomorphism sends a base to a base.
  5. Dec 14, 2015 #4


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    The only thing I have a question about is "p'(0)^p(1)= p(0)= p(-1)". The "^" typically means "and" so one condition is that p(1)= p(0)= p(-1) but the "p'(0)" is incomplete- nothing is said about the derivative at 0. What must be true about it? p in [itex]R^4[/itex] is of the form [itex]ax^4+ bx^3+ cx^2+ dx+ e[/itex] and "p(1)= p(0)= p(-1)" requires that [itex]a+ b+ c+ d+ e= e= a- b+ c- d+ e[/itex]. But, again, what is required of "p'(0)= d"?
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