The ambiguous question came to my last week exam

  1. 1. The problem statement, all variables and given/known data

    If f(x) = x^3,
    show that
    f(a,b,c) = a+b+c

    2. Relevant equations

    I have given exam last week. and i am still searching for this question .. what this is about. is it from Tensor coordinate transformation or some numerical analysis involve here.

    kindly somebody please help to solve or give idea to this question.

    3. The attempt at a solution
  2. jcsd
  3. Mark44

    Staff: Mentor

    As stated here, the question doesn't make sense. Your function f takes a single argument, so you could evaluate f(a), or f(b), or f(c), but not f(a, b, c).
  4. But this question came in final Exam ... It has no error as paper setter claimed ..

    How it will be solved ?
    Anybody kindly help to solve this question
  5. Office_Shredder

    Office_Shredder 4,487
    Staff Emeritus
    Science Advisor
    Gold Member

    If this is the full problem statement as given, it has no solution because it doesn't make any sense. What is the definition of f(a,b,c) supposed to be?
  6. Here you go:

    Given a function f:ℝ → ℝ

    f(x) := x3

    f(a, b, c) := a + b + c

    where x, a, b, c [itex]\in[/itex] ℝ

    QED by trivialization.

    lol now it's formal
  7. HallsofIvy

    HallsofIvy 41,265
    Staff Emeritus
    Science Advisor

    It's hard to be serious about non-sense. And it is still non-sense. However you define "f(x)" that gives you NO information about "f(a, b, c)". They can't be the same function.
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