Recent content by maximus101

  1. M

    Find y'(x) and y''(x) when y is defined with an integral

    Homework Statement For x > 0, define y(x) := x \int_0^{log x} \! \sqrt{1 + e^t} dt -(2/3)(1 + x)^{3/2} Calculate y'(x) := dy/dx and y''(x) := d^2y/dx^2 Homework Equations The Attempt at a Solution would like to work through this with person/people please. Not sure...
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    Matrix proof - augmented matrix - row reduction - column operation - proof

    if this is correct, could you possibly explain how Rank (A) > Rank (B) where B is the m x n matrix we get from A by removing the last column .
  3. M

    Matrix proof - augmented matrix - row reduction - column operation - proof

    ok I get it now, we got the system of equations and we showed that (ii) holds is the same as saying there is no solutions of the linear equations which is exactly what one says (i) ?
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    Is this statement about the rank of a linear map true or false?

    okay, in this case, why is dim U > Rank T ? I'm not sure how to use the fact that it is non-singular
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    Matrix proof - augmented matrix - row reduction - column operation - proof

    okay thanks, that is a lot more clear now we will have m equations: \alpha_1c_{1,1}+...+\alpha_nc_{1,n}=c_{1,(n+1)} . . . . \alpha_1c_{m,1}+...+\alpha_nc_{m,n}=c_{m,(n+1)} we assumed linear dependence, so I think we are trying to prove by counterexample that linear...
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    Matrix proof - augmented matrix - row reduction - column operation - proof

    okay I think I understand a bit better, so considering c1 this will form the first colum of A and it will have m rows, so we will have these equations, for the first row of A it will be c11c1 + c21c2 + ... + cn1cn = c(n+1)1 were cij s.t. i=column j=row and the second...
  7. M

    Is this statement about the rank of a linear map true or false?

    Hey, thank you I understand now. Could you give me an example where (dimU + dimV)/2 > rankT
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    Matrix proof - augmented matrix - row reduction - column operation - proof

    Okay I think perhaps from this information I could get a_1c_1 = c_{n+1} - a_2c_2 - a_3c_3 - ... - a_nc_n and then do this for c_2 ... c_n and have n equations but I'm not sure how we would get a system of m equations from this, unles we made a matrix with m rows. Also I see the...
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    Matrix proof - augmented matrix - row reduction - column operation - proof

    Homework Statement If we let A be the augmented m x (n + 1) matrix of a system of m linear equations with n unknowns Let B be the m x n matrix obtained from A by removing the last column. Let C be the matrix in row reduced form obtained from A by elementary row operations...
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    Is this statement about the rank of a linear map true or false?

    Is this statement true or false if false a counterexample is needed if true then an explanation If T : U \rightarrow V is a linear map, then Rank(T) \leq (dim(U) + dim(V ))/2
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    Addition formulae proof for sin(x + y) and cos(x + y)

    For a fixed y \in R , if f(x) = [sin(x+y)]-(sin x) (cos y) − (cos x) (sin y)and we let E(x) = [f(x)]^2+[f'(x)]^2. How do we prove the addition formulae for sin(x + y)and cos(x + y) by applying the Mean Value Theorem to E
  12. M

    Functions in reals such that inequality holds

    so I did the following: \dfrac{|f(y) - f(x)|}{|y-x|}\leqslant |y-x| was obtained by (y-x)^2=|y-x||y-x| and dividing both sides by |y-x|. then trying to use the fact that \displaystyle\lim_{y\to x}\frac{f(y)-f(x)}{y-x} is the derivative at x but not sure what's next how to...
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    Functions in reals such that inequality holds

    sorry just fixed it
  14. M

    Functions in reals such that inequality holds

    for which f: R \rightarrow R such that \forall x,y\in R does | f(y) - f(x) | \mid \leq (y-x)^2 hold
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